Deltarune

Deltarune
Developers: Toby Fox, 8-4 (consoles, Japanese localization) Publishers: Toby Fox, 8-4 (consoles) Platforms: Windows, Mac OS X, PlayStation 4, Nintendo Switch, PlayStation 5, Nintendo Switch 2 Released internationally: June 4, 2025, June 5, 2025 (Nintendo Switch 2) This game has unused areas. This game has unused code. This game has a hidden developer message. This game has hidden development-related text. This game has unused enemies. This game has unused modes / minigames. This game has unused graphics. This game has unused cinematics. This game has unused items. This game has unused abilities. This game has unused music. This game has unused sounds. This game has unused text. This game has debugging material. This game has a hidden sound test. This game has regional differences. This game has revisional differences. This game has a prototype article This game has a prerelease article This game has a notes page This game has a bugs page

New! It's the "parallel story" to Undertale, by Toby Fox - Deltarune, by Boxy Oft!

The game finally got a non-demo release in 2025, after a quite long almost seven-year wait - or up to fourteen depending on where you start counting from, as Boxy Toby had the dream that inspired Deltarune all the way back in 2011. Even after all this time, it currently only features Chapters 1-5. Future chapters are planned to be released as free updates, with Chapter 6 planned for 2027, and Chapter 7 planned for an unknown future time.

With such a long development cycle, it's no surprise that a lot of unused content gets left over, ranging from entire cut areas in some chapters, to unused enemy attacks, game mechanics, debug content, and more - and if you dig deep enough, you can even find some very, very interesting things which might not have just been left there by accident.

The game makes use of a peculiar GameMaker feature that was added specifically for Deltarune, which allows individual chapters to effectively be stored as entirely separate games and swapped between on-the-fly. Each chapter comes with its own data.win file and quite a bit of duplicated content, with only music files being shared between them. Thus, this page has been split up on a per-chapter basis, with the main page only being used for things which are present across multiple chapters in a significant or changed way.

Sub-Pages

Prototype Info

Prerelease Info

Notes

Bugs

Unused Content by Chapter

Chapter 1 The Beginning

Chapter 2 A Cyber's World

Chapter 3 Late Night

Chapter 4 Prophecy

Chapter 5 Festival Day

Non-Chapter Specific

Version Differences FIXED WITHOUT ISSUE

Preceding Chapter Leftovers

Many sprites and sounds from a previous chapter will be left over in the next one, regardless of if they're used in that chapter or not. This is likely due to the chapters being built off one another, as well as being a remnant from when each chapter was in one data file before the game_change function was implemented. The exceptions to this are typically sprites that are unlikely to be needed in future chapters, such as Ramb's sprites being exclusive to Chapter 3's files and very cutscene-specific sprites being exclusive to the files of the chapter they appear in.

Unused Graphics

obj_npc_facing

This sprite, spr_placeholder, is the default sprite of the object obj_npc_facing, which is used for most NPCs capable of facing different directions (hence the name). The sprite is likely present simply to make these objects identifiable in the editor – it is changed to an NPC's sprite (Toriel's by default) upon creation.

(Source: Original TCRF research)

Placeholder Kris Sprite

An unused placeholder sprite for Kris, named spr_krisplace. It's used as the "default" sprite for the party member objects in battle, while programming from the parent object tells the game which object should use which party member's sprites.

(Source: Original TCRF research)

Doors

Designs for the marker objects used to set Kris's position upon entering a room through a door introduced since the release of Chapter 2, using a cleaner letter design and including a silhouette of Kris, as well as adding letters R-V, with the S marker using the Cool S. There were also "any" markers added, which go through the entire alphabet and have numbers for each letter.

(Source: Original TCRF research)

Like with the markers, the door objects also got "any" versions, though there aren't quite as many of them in comparison.

(Source: Original TCRF research)

Chapter 1 Demo Noelle Portraits

spr_face_nX
spr_face_n_matome

Noelle's original dialogue portraits from the Chapter 1 Demo still exist in each Chapter's files as spr_face_n0-spr_face_n9, being replaced with spr_face_n_matome in Chapter 2 and retroactively replaced in Chapter 1. She had a much rounder jaw, longer hair that was cut off by the bottom of the frame, and her eyes were closer to her hair and further from her nose. A couple of them are notably animated, a feature that was lost in her new portraits (and most portraits in general) due to the game adopting a new system of storing each character's portraits as one sprite rather than multiple.

(Source: Original TCRF research)

Extra Chapter Numbers

From Chapter 2 onwards, a chapter number sprite is displayed beneath the game's logo with its frame corresponding to the current chapter (dictated by the global.chapter variable). This includes the expected Chapter 2-7 graphics, along with an unused version for Chapter 1, which doesn't include/display this sprite. Furthermore, it also includes graphics for Chapters 0, 8, 9 and 10, none of which appear in the chapter select screen or otherwise have had any indication of their planned existence.

The Chapter 0 and 1 graphics were likely added for convenience so that each frame of the sprite would correspond to a Chapter number properly, but it's unclear why the Chapter 8-10 ones exist. As Toby Fox has explicitly stated in interviews that there will be seven chapters, these were most likely either left here as a red herring, or the developers themselves were simply uncertain of how many chapters there would be at the time the sprite was made.

(Source: Original TCRF research)

Unused Objects

obj_CHAPTER_SELECT_old

Old	Current

An old version of the chapter select, leftover from v2 of the LTS Demo, could be found in the files before v22. This version is from before the chapter select was reprogrammed in v3 of the demo, so it's very different internally. The changes are as follows:

• The game window's title is still set to "DELTARUNE Chapter 1&2".
• Only Chapters 1 and 2 can be selected.
• After selecting a chapter, 12 frames need to pass before the player is allowed to proceed with or back out of starting it.
• The lines separating the chapters fade in from the bottom rather than the top.
• It's missing the option to switch to Japanese.
• The text and icons are all further from the sides of the window.
• The chapter icons are displayed incorrectly due to changes in how they're stored.
• The copyright information was moved from the bottom right to the bottom left to make space for the Shadow Crystal UI.
• The version is "DELTARUNE v2" and the copyright years are still listed as 2018-2024.
• The stars that appear to indicate which save files were completed in a chapter don't exist.
• The text for continuing and starting a new chapter before all available chapters are completed is formatted differently.

Attempting to start a chapter will crash due to the chapter starting sounds being renamed, but fixing this by making it call the proper audio files will make it function properly again.

Unused Text

Failsafe Text

Throughout Deltarune, as with Undertale, there are many places in the dialogue where particular text is shown depending on the value of some variable. In many of those places, failsafe text is defined, which will be displayed if there was no other text defined for the particular value of the checked variable.

Objects and Scripts

There are several generic objects and scripts used to display text for multiple different NPCs (and other interactables) throughout the game. They often have a general failsafe message for if the particular variable value (e.g. room ID, item ID, etc.) isn't defined.

Monster Encounters

The default message for the text that appears at the start of battles in scr_enountersetup, which can be seen in-game by starting a battle with an encounter that's not uniquely defined. In Chapter 4, it can also be seen in an encounter with a Wicabel and Organikk due to an oversight where they don't have a battle message defined.

English	Japanese
* It is known.	＊ 既出だ。

Door

Shortcut door choice (though this is unused even if the choice is undefined):

English	Japanese
* (But nothing happened.)	＊ (どういうわけか 　 もう　そこにいる)

Rhyming NPC Dialogue

obj_npc_facing, obj_npc_room, and obj_npc_room_animated, respectively:

English	Japanese
* Is that a cut on your face, or part of your eye?	＊ キミの顔…　それは傷かい？ 　 それとも　目なのかい？
* The gash weaves down as if you cry.	＊ パックリ割れた　切り傷が 　 まるで　涙のあとみたい。
* The pain itself is reason why.	＊ 理由は　その　痛み自体。

These three rhyming lines appear to be connected. It is worth noting that they describe Undertale‍ '​s "mystery man" (the character assumed by many to be Gaster) suspiciously well.

(Source: Original TCRF research)

Symbols

obj_npc_sign (primarily used for signs):

English	Japanese
* You can't read these symbols... * Or maybe it's the handwriting.	＊ 記号を　解読できない… ＊ 手で書いてあるせいかもしれない。

This line is a reference to similar lines in Sans's workshop in Undertale (these lines are not in Deltarune; they're just included here for illustrative purposes):

* (Blueprints.) * (You can't read the symbols they're written in...)

* (... or maybe it's just the handwriting.)

* (Looks like they relate to some kind of strange machine.)

(Source: Original TCRF research)

Seizure

obj_readable_room1:

English	Japanese
* Suddenly, your body seizes up. * What are you looking at?	＊ とつぜん　からだが　けいれんした。 ＊ いったい　なにを　みている？

(Source: Original TCRF research)

Base Interactable Objects

obj_interactablesolid and obj_readable, respectively (which serves as the bases for actual interactable objects):

English	Japanese
* Can you see me...?	＊ ボクが　見える…？

(Source: Original TCRF research)

Generic Error Messages

In Chapter 2 onwards, if debug mode is enabled, these messages all become basic error messages explaining what the problem is.

Object	Text
obj_npc_room	* [NO TEXT] (obj_npc_room)
obj_npc_sign	* [NO TEXT] (obj_npc_sign)
obj_npc_room_animated	* [NO TEXT] (obj_npc_room_animated)
obj_readable_room1	* [NO TEXT] (obj_readable_room1)
obj_npc_facing	* [NO TEXT] (obj_npc_facing)

Game Initializers

scr_gamestart

Among other things, this script defines default choice options:

English	Japanese
Normal
Kris	クリス
Susie	スージィ
Ralsei	ラルセイ
G BODY
Yes
No
Maybe
Don't know
Home	ホーム
Kris	クリス

(Source: Original TCRF research)

obj_initializer

This object's Create script defines default messages (which were seemingly at one point used for testing).

Small messages:

RALSEI: i1

SUSIE: * i3

Normal messages:

RALSEI: * i4

SUSIE: * i5

(followed by Susie's above small message)

* i6.

TORIEL: * i7!

(Source: Original TCRF research)

SAVE Files

If a save file exists but dr.ini doesn't exist, then one of the following three strings will be displayed in place of the file's name:

FILE0

FILE1

FILE2

(Source: Original TCRF research)

Save Name

English	Japanese
Kris	クリス

Code that doesn't work anywhere, from obj_savemenu's Create script.

(Source: Original TCRF research)

Name Hack

English	Japanese
???	？？？

Since the Light World menu is reused from Undertale, the stat menu will still respond to a name longer than 6 letters, though now with confusion. The reason is likely that the name is harder to change this time around as it's always set to "Kris", making it impossible to change through save editing. This text can be seen by changing the value of global.lcharname in scr_gamestart from "Kris" to a name longer than 6 letters, and will overwrite the "Since Chapter" message that shows the chapter the player started that file from.

Unused Enemies

#1: Enemy

Enemy (obj_placeholderenemy) is an unused placeholder enemy evidently used for testing. It is defined as a failsafe in a few different places, and so has a few other names. It uses Rudinn's sprites, though it has different text, ACT options, and stats.

TESTOBJECT is defined by obj_initializer, and Enemy is properly defined in scr_monstersetup. Oddly, the name defined for it in scr_gamestart is often changed between chapters; it was first called G BODY in Chapter 1, then Chapter 2 changed it to ECHIDNA, Chapter 4 changed it to TERUTERUBOUZA, and Chapter 5 changed it to WEATHER DOLL. Chapter 4's name is similar to teru teru bōzu, dolls that are hung outside doors and windows in Japan in hopes of bringing sunny weather, which Chapter 5's name seems to describe as well.

TESTOBJECT			G BODY/ECHIDNA/TERUTERUBOUZA/WEATHER DOLL			Enemy
Attack	3		Attack	3		Attack	7
Defense	2		Defense	2		Defense	0
HP	20		HP	20		HP	130
			Spare point	0		Spare point	10
						EXP	0
						D$	0

Battle Messages

Normal battle messages:

* Placeholder Message A.

* Placeholder Message B.

* Placeholder Message C.

* Placeholder Message D.

Enemy Messages

Messages that would be spoken by the enemy, randomly chosen between:

Message A

Message B

Message C

Message D

...were it not for this line, which replaces the above lines every time:

WlyWlyWlyWly WlyWlyWlyWly WlyWlyWlyWly WlyWlyWlyWly

Message shown after using 'Victory (S)' (see below) at the end of the enemy's turn:

A special scenario occurred!!

ACT

ACT options (effects detailed below):

English	Japanese
Check	ぶんせき
Warning	けいこく
Victory
Victory (D)
Victory (S)
Lecture	せっきょう

'Check' text (note the incorrect stats):

English	Japanese
* ENEMY - AT 1 DF 1 * I am your adversary.	＊ エネミー - ATK 1 DEF 1 ＊ 私は　敵です。

'Warning' text:

* You warned the enemy. * It guarded from Susie's attack.

(Warned)

'Victory' text (makes the enemy spareable immediately):

* Its body was filled with a kind feeling.

'Victory (D)' text (makes the enemy spareable after the enemy's next turn):

* Its body will result in a kind feeling at the end of the combat.

'Victory (S)' text (makes the enemy say a message and run away, following its next turn):

* Its body will result in a speech after attack.

'Lecture' text:

* Its body became tired.

(Tired)

(Source: Original TCRF research)

Unused Settings

There are several flags stored in each chapter's save file for settings that normally can't be changed in-game.

Disable Screen Shake

Flag 12 (found on line 329 in Chapter 1 and line 565 in Chapters 2+) allows you to toggle the screen shake effects. When set to 1, all screen shakes will be disabled. A variable called shakeoff is still present in the config menu's draw code, being set to either "OFF" or "ON" depending on if flag 12 is set to 0 or 1.

Alternate Attack Mode

To do: Replace this video with a more straightforward, professional one.

When flag 13 (found on line 330 in Chapter 1 and line 566 in Chapters 2+) is set to 1, it enables an unused method of attacking where each party member uses a different key to attack. The first member uses the Confirm button (Z by default), the second member uses the Cancel button (X by default), and the third member uses the Menu button (C by default). Note that in Chapters 1 & 2, this mode will properly light up Ralsei's attack box, unlike the normal mode, though it won't return to green due to the same bug that prevents the normal mode from lighting the box up in the first place. This mode's code wasn't updated upon Noelle being added in Chapter 2, so her attack box won't light up at all while using it.

Battle Cursor Memory

When flag 14 (found on line 331 in Chapter 1 and line 567 in Chapters 2+) is set to 1, each member's selections from their previous turn will be kept instead of reset. This extends from the main action menu to all the sub-menus.

SFX and Music Volume

Flags 15 and 16 (found on lines 332 & 333 in Chapter 1 and lines 568 & 569 in Chapters 2+) control the volume of sound effects and music respectively, which are options that cannot be changed normally, as only Master Volume can be changed. Code still exists in the step event of obj_darkcontroller (the object for the Dark World's pause menu) to change these values, sound effect volume being changed when global.submenu is set to 31 and music volume being changed when global.submenu is set to 32. Their values are both changed by 0.5 (5%) at a time instead of 0.2 (2%) like Master Volume is. Interestingly, a variable called musvol containing the music volume's current percent is still set for the config menu's draw code, but it's never used.

Unused Mechanics

Talk Button

Hidden in the Dark World menu's code is a fifth button for TALKing. It's supposed to be placed in the middle of the four buttons, but is programmed to be skipped when drawing the menu buttons and moving the cursor left or right to select an option, along with an extra check to cancel selecting it and reset the menu cursor position if the option was somehow selected. The button would have been used for talking to your party members about the room you're currently in (à la calling Papyrus in Undertale), but was likely scrapped due to the sheer amount of dialogue that would need to be written to account for story progress and current party members. scr_talkroom, the script that would've held all the dialogue, still exists and is ran when using this button, but any dialogue that may have been written was stripped out, leaving it to use a single placeholder line instead.

Interestingly, using this button in the second timed puzzle room in Chapter 1 will change the text for failing too many times.

Multiple Attack Bolts

Another feature that would've returned from Undertale was a character having multiple attack bolts depending on their weapon. Each weapon has a weaponbolts variable for how many bolts the weapon should give, but they're all set to 1, and each character's charbolt variable in the code for creating the attack UI is hardcoded to 1 anyway regardless of their weapon's bolt amount. Changing the hardcoded values or making the game set each character's charbolt variable to their current weapon's weaponbolts variable will show that this feature is fully functional. The damage done to an enemy will be multiplied by the amount of bolts however, which is unclear if it's a bug or not.

Overworld Spell Use

The game supports using certain spells in the overworld from the status menu when the party has enough TP, calling the script scr_spell_overworld to do so. Battles usually set TP to 0 upon ending to prevent this from happening, though it's unintentionally possible in Chapter 1 on rare occasions where TP isn't reset, such as after the battle between Susie and Lancer. The only spell that's usable in the overworld is Heal Prayer, healing 100 HP being just as if an item were used. Starting with Chapter 2, this was completely removed by making Heal Prayer no longer usable in the overworld.

Ambushing

Starting with Chapter 2, the game contains a partially unused mechanic for enemies ambushing the player when starting battles. obj_chaseenemy, the object commonly used for overworld enemies, contains unused code for shooting basic diamond bullet objects called obj_encounter_bullet at the player when its test_release_bullet variable is set to 1. If one of these bullets hits the player, the global.ambush variable will be set to 1 and the party will shake while (with the exception of Noelle) using a hurt or shocked sprite, after which obj_testoverworldenemy, the object often used when touching an enemy to start battles, will run code to play the sound snd_battleenter while immediately starting the battle, instead of playing two instances of snd_tensionhorn first. When the battle starts, the enemy will have its turn first.

The reason this mechanic is only "partially" unused is that the functionality for starting battles on the enemies' turn with with the global.ambush variable is still occasionally used for some fights, such as Clover and Tasque Manager's in the Dojo.

There is also unused code for the player ambushing enemies instead. When hitting enemies while in sword mode (more on that below), an explosion animation will play over the enemy, global.ambush will be set to 2, and obj_testoverworldenemy will have its washit variable set to 1, which makes the object play snd_break2 while immediately starting a battle with TP set to 25%. The enemies will also have their firststrike variable set to 1, but this variable is never checked by the game. Interestingly, an encounter with two Virovirokuns in Chapter 2 has alternate battle start text for if the enemy was ambushed.

Sword Mode

Starting with Chapter 2 obj_mainchara, the object for Kris in the overworld, contains code for an unused mechanic where they'd use a sword to attack in the overworld when their swordmode variable is set to 1. In this mode, Kris can only face left or right even if they're moving up or down, and pressing the CONFIRM button will freeze them in place for a moment and make them "slash" by spawning obj_swordhitbox and playing a slashing sound. By default obj_swordhitbox won't function properly due to not having a sprite assigned to it, but assigning it one (like Kris' slashing sprite, for example) will display the object at 20% visibility and allow it to hit objects that are children of obj_swordobjparent, such as enemies and test objects present in room_cutscene_tester. An unused object called obj_swordarea will put Kris in this mode while they're touching it as long as an object that's a child of obj_swordobjparent is also touching it, implying the mechanic would be restricted to specific sections of rooms. The graphics for this mechanic appear to have not been implemented, as Kris will use their right facing sprite the entire time, flipped to match the direction they're facing.

The concept of Kris using their sword in the overworld would later be somewhat brought back with Chapter 5's platformer mode.

Debug Mode

To do: What exactly works in each chapter?

Debug mode has largely been stripped, but some mechanics of it still work (and some testing maps need it enabled to work correctly), with the extent to which this is the case varying by chapter. Chapters 1 and 2 have nearly all debug functionality stripped despite it originally being present in the demos. Later chapters, especially 3 and 4, have more functionality intact, but they crash at various points without further modifications.

The easiest way to enable the remaining debug mode features in each chapter is to use UndertaleModTool's built-in UT/DR Debug script on the chapter's data.win file, which will also fix the crashes in Chapters 3 and 4. See the notes page if you want to know what this script is actually doing.

The following debug features are shared across some chapters:

• Holding G records and saves a gif to Deltarune's AppData folder
• Pressing S allows you to save your game anywhere
• Pressing L will instantly load your current save
• Pressing Z shows the hitbox for interacting with objects
• Pressing ~ speeds up the game to 150 FPS until it's pressed again
• Pressing Ctrl + ~ slows down the game to 10 FPS until it's pressed again
• Pressing ⇧ Shift + Ctrl + N (LB/LT + RB/RT + Y on controller) activates no-clip in Chapters 3 and 4
• Pressing ⇧ Shift + Ctrl + 0 (LB/LT + RB/RT + Select on controller) sets global.interact to 0 in Chapters 3 and 4
• Various keys allow you to easily traverse between rooms:
  • Pressing the Insert key brings you to the next room ID
  • Pressing the Delete key brings you to the previous room ID
  • Pressing Home + 1 brings you to the Cyber World intro room (Chapter 2 only)
  • Pressing Home + 2 brings you to Kris's bedroom
  • Pressing Home + 3 brings you to your Castle Town
  • Pressing Home + 7 brings you to the Legend cutscene
  • Pressing Home + 8 or Home + 9 brings you to room_battletest

Debug Menu Remnants

There are remnants of a debug menu in each chapter's files, mainly in scripts prefixed with "scr_84_", implying the menu was originally created by 8-4, Ltd. during the japanese localization of Chapter 1's development. Although it cannot be used anymore due to a vital script being dummied out, its companion scripts are still intact.

Script	Function
scr_84_debug()	The aforementioned vital script that was dummied out. Unlike most debug content this script was even dummied out of the demos, though thankfully Chapter 1's version of this script was left in the Nintendo Switch port of the Chapter 1 Demo, revealing this script would have contained the code for setting up, controlling, and drawing the menu. In the Chapter 1 and 2 demos and Chapters 3 and 4, this script is called in obj_time's Step and Draw GUI events, the latter of which was updated in Chapter 3 to add a transparent blue background while the menu is active. This script being dummied out is actually the reason for Chapter 3's boards crashing in debug mode, as they try to check if the "show room name" setting from this menu is enabled, which causes an error when the menu is stripped out.
scr_84_add_menu_item()	Adds an option to the debug menu, usually having 3 arguments passed into it: a string that the menu reads to figure out how the option should function, a value to be used as an argument by the option, and a string to be displayed in the menu as the option's name.
scr_84_draw_menu()	Draws the menu. Was updated in Chapter 2 to highlight the selected options in yellow, and further updated in Chapter 3 to change how drawing groups works.
scr_84_push()	Used to set up a group in the menu, allowing more options to be hidden until the group is selected.
scr_84_pop()	Ends the current group being set up.
scr_84_draw_text_outline()	Draws an outlined version of the text passed into it as an argument. While technically not unused since it would eventually end up being used for a couple huds in Chapters 3 and 4, this script was originally only created and used for this menu.
scr_84_is_digit()	Checks if the argument passed into it is between 0 and 9. Not actually used in the menu (or anywhere for that matter), but it may have been intended for it.

Rhythm Game (Lightners Live)

Editor

To do: Add screenshots.

Chapters 3-5 contain an entire chart editor within the files, which supports the creation, saving, and loading of charts. This requires debug mode to be active to work fully. In Chapters 3 and 5, the map is protected by Dogcheck, and requires modifying the files to load. Chapter 4 just requires a save edit to load room 40266.

It supports editing all three sections (Drums, Guitar, and Vocals) along with playing each of these charts, though there's nothing programmed in to allow playing the third column of vocals. Starting in Chapter 5, Vocals is instead labeled "Tambourine" for all tracks except Raise Up Your Bat, Flower Man, and curiously, It's TV Time and 4rd Sanctuary.

There's also no way to chart for specifically Normal and Hard, as Hard mode just tightens note timings and doesn't change charts.

Rhythm Game Debug

To do: Footage? Also, this should maybe go under the Debug Mode section instead.

If debug is enabled, the rhythm game has a debug mode for itself by pressing O while playing a song. This was stripped out in Chapter 5.

This displays the current FPS and FPS_real (possibly framerate for the underlying rhythm game's hit registering system) above Kris. These will turn red whenever the game's framerate drops under 30.

In the top left, four items are shown: track pos, showing how far you are in the song, fame, which is your 'health', and two numbers- the song's 'note time' and the track position divided by the meter.

• Pressing I will enable auto-play. This requires you to have pressed O prior to pressing I.

• Pressing U causes the game to swap different internal modes, and pressing too many times quickly can cause the game to crash.
  • Pressing U once causes it to switch to auto-play; a second time switches it to auto-play with the control prompts enabled.
  • A third time greys out Kris's highway.
  • A fourth time just completely disables input or gameplay.
  • A fifth time causes the game to block out Kris's and Susie's highway.
  • A sixth time completely disables the rhythm game UI but gives you back control.
  • A seventh time makes Kris, Susie, and Ralsei go into their standing pose, and the stage flashes red.
  • An eighth time sets the game into the tutorial song with just Kris's highway.
  • A ninth time enables Susie's and Ralsei's highways.
  • Pressing U more than 9 times repeats the cycle with the tutorial song selected.

• Pressing/Mashing 4 while starting Raise Up Your Bat will skip the intro. This sometimes causes the song to freak out, but should usually work.

• Pressing P lets you pause the rhythm game. Simple as that. Pausing causes notes yet to appear on the highway to display.

• Pressing R restarts the song.

• Pressing F5 causes the rhythm game to instantly end, showing the results.

• Pressing F6 brings the player to the fail screen (Retry/Quit).

• Holding Left ⇧ Shift then - or + will cause the song's volume to go down or up accordingly.

BIG Combo

If the note combo is above 999, the display on the chart will stop and simply say "BIG" where the combo number would be. The "MAX COMBO" meter on the bottom right and the results screen will continue counting past 999, however. As no song currently included in Deltarune has over 999 notes, this can only be seen if the player waits a very, very long time during Tenna's explanation of the minigame in Chapter 3.

As of Chapter 4 version 1.03 and in Chapter 5, this can also now be seen when playing "Raise Up Your Bat" while Susie isn't in the party. Around the end of the song her lane will display a "BIG" combo.

Freeplay Mode

This page or section needs more images. There's a whole lotta words here, but not enough pictures. Please fix this.

If the freeplay variable in the rhythm game object is set to a negative number, it will show a menu letting you select which song to play. In Chapter 3, this menu is locked behind debug mode, requiring that the Cancel button be held down while loading the room during the physical challenge version of the minigame (but NOT the A-rank version, weirdly enough). However, in Chapter 4 this menu can be accessed by holding minus on the numpad as the minigame starts, and this does not require debug mode! Unfortunately the song titles in the Chapter 4 version don't actually correspond to the songs that will be played, but it does allow some of the special Chapter 3 songs to be accessed in normal play.

In Chapter 5, the menu is entirely inaccessible without adding code somewhere that sets freeplay to negative, because nothing exists that does this anymore.

Allcaps Asset Names

To do: More stuff, like the audio: GALLERY, KEYGEN, TV_GAME.

The window captions used throughout Chapter 1 change in some cases to denote context; the 'light world' sections use title case (e.g. "The Beginning", "The Return") and the 'dark world' sections, along with everything else, use upper-case (e.g. "THE DARK", "CONTACT", "DELTARUNE").

Internally, most of the game's assets are named using a similar though distinct convention of upper/lower case. Unlike the window captions, the "Dark World" assets, like the "Light World" assets, use lower case, abbreviated prefixes (in Undertale, these were the only prefixes used). Allcaps prefixes/names are only used in the following contexts:

• The CONTACT sequence at the start of Chapter 1 and everything associated with it.
• The logo screen and main menu (both versions of it).
• The game over ("FAILURE") screen.
• The dogcheck room.
• "UNUSED", a series of unique "scripts" found in each chapter.
• Most variable names in DEVICE scripts.
• The ominous grinning face with pink and yellow eyes, with the internal name of "FRIEND", though in Chapter 3 it's simply referred to as "_" instead.

These are effectively all of the "out-of-bounds" sections of the game, as it were, with the exception of the ending credits and the "FRIEND".

Below is a full list of the used prefixes:

Type	Normal prefix	Allcaps prefix	Notes
Sound	snd	AUDIO
Music	mus		Most of the music doesn't use a prefix, but the few that do use these.
Sprite	spr	IMAGE
Background	bg
Script	scr		"UNUSED" is the only allcaps script. One would have expected the "PROCESS" prefix to be for scripts, but the only things that use it are two objects.
Font	fnt
Object	obj	DEVICE
		PROCESS	As mentioned above, this seems like it should logically be the script prefix.
Room	room	PLACE	"ROOM" is also used once, for ROOM_INITIALIZE (room 0, the startup room, which immediately sends you to PLACE_CONTACT, PLACE_MENU, or room_legend, depending on save progress).

Variable names within allcaps objects also follow this convention, mostly being in allcaps as well, in addition to sometimes utilizing slightly more verbose terminology. One notable counterpart for a common local variable is EVENT, used in place of con (condition/conversation).

(Source: Original TCRF research)

Music/Sound Metadata

To do: Missing Chapter 3/4/5 stuff.

Similar to Undertale and its demo, some audio files contain metadata. Most of it seems to come from FL Studio.

Chapter 1

(most files)
Name	Content
ENCODER	FL Studio
mus/fanfare.ogg ("Fanfare") snd_rurus_appear(_ch1).ogg
Name	Content
Software	FL Studio 10
mus/checkers.ogg ("Checker Dance")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	160
DATE	2016
mus/kingboss.ogg ("Chaos King")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	147
DATE	2016
snd_usefountain(_ch1).ogg ("Your Power")
Name	Content
encoded_by	LAME in FL Studio 10
TBPM	118
date	2016

Chapter 2

mus/alarm_titlescreen.ogg
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	165
DATE	2017
mus/berdly_theme.ogg ("Berdly")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	98
DATE	2019
mus/noelle_ferriswheel.ogg ("Ferris Wheel")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	200
DATE	2018
mus/noelle_normal.ogg ("Lost Girl")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	75
DATE	2018
mus/giant_queen_appears.ogg ("Giga Size")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	125
DATE	2019

Chapter 3

mus/ch3_board1.ogg ("Sandy Board")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	147
DATE	2019
mus/tenna_battle_preview.ogg mus/tenna_battle_preview_crisp.ogg
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	148
DATE	2021
mus/knight.ogg ("Black Knife")
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	295
DATE	2018

Chapter 4

mus/church_zone2_alt_longer_test.ogg
Name	Content
Encoder	Lavc60.31.102 libvorbis
Compatible Brands	isomiso2mp41
Handler Name	SoundHandler
Language	und
Major Brand	isom
Minor Version	512
Vendor ID	[0][0][0][0]
DATE	2021
(some files under the root folder - seems to be added by GameMaker)
Name	Content
encoder	Lavc libvorbis

Chapter 5

mus/ch5_inversion_lake_chant.ogg
Name	Content
Encoded by	LAME in FL Studio 10
BPM (beats per minute)	130
DATE	2024
mus/shop_3.ogg ("Shop 3")
Name	Content
DATE	2019
mus/dogroom.ogg mus/mus_date_fight.ogg mus/mus_date_tense.ogg
Name	Content
encoder	Lavc56.12.101 libvorbis

Misc.

snd_hit(_ch1)
Name	Content
IART	Don Ralke; Sherman Bros.
ICRD	1972
INAM	Snoopy, Come Home
snd_spearappear(_ch1)
Name	Content
ICRD	2013
snd_won_skipping
Name	Content
ICMT	hackerman

The mentions of "LAME in FL Studio 10" imply that some files were converted from MP3s - LAME is a MP3 encoder.

Due to reusing Undertale's snd_hit file for snd_hit_(ch1), the "Snoopy, Come Home" (which is the title song for the 1972 movie with the same name) metadata is intact.

(Source: Original TCRF research)

Chapter Inconsistencies

Despite the game reaching its full release, there are some odd inconsistencies between the currently available chapters.

Enemy Targeting

In Chapter 1, one or more specific party members will be targeted for an attack, and they'll have a target graphic placed over them before the attack starts while the rest are darkened. Targeted members will be the only ones who take damage during the attack until they're downed. In every subsequent chapter, the target graphic was removed, and aside from a few instances, a random party member is chosen to be damaged each hit.

Invisible Mercy

In Chapter 1, the enemies' mercy meters and percentages aren't visible to the player in battle. Granted, the only enemy whose mercy meter doesn't fill up immediately upon successfully pulling off an act in this chapter is Clover, but it's a notable oddity nonetheless.

Unkillable in Overworld Bug

Due to a coding error in Chapter 1, if any character's HP value is exactly 2, it will be impossible for the party to be killed by hazards in the overworld. This was fixed in future chapters.

S/R/N-Action Debug Display

In Chapter 2, holding A while in a character's ACT menu in battle will display a box beside the enemies that contains the text for their S/R/N-Action depending on if they're defined and what characters are currently in your party. Starting with Chapter 3, this function was locked behind debug mode, meaning its availability in Chapter 2 was likely an oversight.

Chapter 3 Invincibility Frames

In Chapters 1, 2 and 4, the soul is nearly always given 40 invincibility frames after being hit. However, for some odd, unknowable reason, Chapter 3 changes this to 30 invincibility frames instead.

Pink/Twin Ribbon TP Gain Nerf

From Chapter 3 onward, the Pink Ribbon and Twin Ribbon were given a TP Gain nerf not communicated by the game. The Pink Ribbon will reduce TP gain by 20%, while the Twin Ribbon will reduce TP gain by 25%. This nerf stacks with each of these items equipped, which can result in TP actually being taken away if enough are obtained through hacking.

Rude Buster Damage Boost Lock

Rude Buster's damage boost mechanic was made more strict between Chapters 2 and 3. Before Chapter 3, pressing Z at all would cause you to deal the maximum damage bonus, due to a bug in the logic which caused any boost to be the maximum boost. This was fixed starting with Chapter 3, making it necessary to time the attack correctly.

Ralsei Attack Box Bug

In the first two chapters, Ralsei's attack box won't light up while attacking. This is the result of a coding error where the game should set pressbuffer[1], pressbuffer[2], and pressbuffer[3] to 5 when pressing the attack button and then decrease them by 1 each frame, but mistakenly does this for pressbuffer[0], pressbuffer[1], and pressbuffer[2] instead. This was fixed starting with Chapter 3.

Kris Slide Animation

Kris's slide animation was updated in Chapter 3, being completely redrawn and given more than one frame to be consistent with Susie and Ralsei's. In Chapter 4, they still use the updated spritework, but only one frame is displayed due to the slide objects not being updated to set Kris's animation speed like they were in Chapter 3. Chapter 5 retains the same error as Chapter 4, aside from on the first sliding wall early in the Cliffs area where the animation does play, albeit faster than in Chapter 3.

Note that their unused Light World sliding sprite was left unchanged.

Chapter 1+2	Chapter 3	Chapter 4+5

Alternate Project Name

Although the game's project is simply named "DELTARUNE", there seems to be an alternate name used internally by the developers: "sunkus". This can be seen in the igor.output.manifest file in the game's install folder, where it's called "<build date>_SUNKUS", leftover build paths in the options.ini files of the Nintendo Switch versions of the game and its demos, and in the files of Chapters 3 and 4, where many keyboard functions were replaced with custom functions with "sunkus" in the name, such as "sunkus_kb_check" and "sunkus_kb_block".

Although it's unclear why the project is called sunkus, it's possible that it was named after Circle K Sunkus, a Japanese convenience store chain that was rebranded in 2016.

Leftover Build Paths

To do: Check all console versions, and their updates to see if anything changed for them. Chapter 5 versions.

Within the igor.output.manifest file left in the game's install folder on PC is a build path for the game, including a build date.

Version	Release Date	Build Date	Path
v1.0	June 4, 2025	June 2, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250602_SUNKUS.zip
v1.01A	June 6, 2025	June 6, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250606_SUNKUS.zip
v1.01B	June 8, 2025	June 7, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250607_SUNKUS.zip
v1.01C	June 9, 2025	June 8, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250608_SUNKUS.zip
v1.02	July 8, 2025	June 18, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250618_SUNKUS.zip
v1.03	July 23, 2025	July 2, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250702_SUNKUS.zip
v1.04	August 5, 2025	July 23, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.104/bin/igor/windows/x64/250723_SUNKUS.zip
v1.05	August 26, 2025	August 21, 2025	/ProgramData/GameMakerStudio2-LTS/Cache/runtimes/runtime-2022.0.3.115/bin/igor/windows/x64/250821_SUNKUS.zip

Although the Nintendo Switch version has no manifest file, it includes what seems to be a path to a Nintendo SDK and a build path for the game in its options.ini file, though it lacks a build date.

[LLVM-Switch]
SDKDir=C:\Nintendo\sunkus\NintendoSDK
UseNEX=False
UseNPLN=False
nMeta=C:\Users\sodon\Projects\01-DELTARUNE\20-Launcher\sunkus-launcher\DELTARUNE\options/switch/SWITCH_FULL/application.nmeta

(Source: Original TCRF research)