=== Taking the stairs ===

Stairs are radically different in Halls of Mist compared to most other
roguelikes.

Stairs up take you straight back to the town. Stairs down take you somewhere
near your maximum depth.

The Thin White Duke isn't sleeping, he's preparing for war and strengthening
his position in the dungeons. The minimum difficulty level (Min Depth, shown on
your character sheet) increases by one each time you take the stairs down.

When you take the stairs in town, you are asked where you want to navigate. Do
you want to descend to (e)asier depth than before, (s)ame depth, (l)ower depth,
or perhaps (d)ive two levels deeper? So you can still control how fast you
dive, as long as your current depth is at least as deep as the minimum depth.

If you take the stairs down while in the dungeon (skipping the trip to the town
and back), you have the choice of descending even faster if you like, up to
three levels for every down staircase.

If you dive fast, you'll get some wiggle room on deeper levels. For example,
you could dive fast early, and then return to level 15 several times.

Winners who dove fast get a big score multiplier.

The Thin White Duke resides on the dungeon level 48. If your Min Depth ever
grows beyond that, you lose the game.


=== How do these changes affect gameplay? ===

Slowly accumulating power on easy dungeon levels isn't really an option.

Diving fast has many benefits, but it is also more dangerous in this roguelike.
I hope that the player will usually navigate to the "just right" difficulty
level for his power level. In this roguelike, you have to live on the edge.

To keep up with the ever-strengthening monsters, it is recommended that you try
to clean each level throughoutly. This is how many people like to play anyway,
and in this roguelike it's the best strategy.


=== The flavour behind the stairs mechanic ===

The travel between dungeon levels takes a lot of time, let's say a week.
Traveling, resting, etc. inside a dungeon level is "tactical time" and doesn't
really matter.

Every week the Thin White Duke also strengthens his position in the dungeons.
This increases the minimum danger level because Duke's agents are everywhere.
If the player wants he can advance further than this to the areas in Duke's
direct control, to even more dangerous dungeon levels.

In about a year of game time (48 weeks) the Duke has finished his negotiations
with the Dragons of Chaos and the Demons of Aether, and conquers your home
realm. You have lost your mission.

Of course the timekeeping is very abstract, and is not completely logical. But
this is the basic thinking behind the rules.

   "It takes a week to travel between dungeon LEVELS? Dungeons I'd understand,
   but individual levels?" (ekolis on the angband.oook.cz forums)

Each dungeon level is an outpost under the Duke's control, with large sections
of wilderness between them.

And its not just boring wilderness. The Halls of Mist is a dungeon complex that
connects worlds. Some of those worlds have completely different laws of nature.
Navigating the beast isn't exactly simple.

The dungeon keeps magically shifting, and there's always that hallucinary blue
mist confusing you. And labyrinths, those crazy labyrinths everywhere. Who was
the idiot who built this damn thing?

For all these reasons and more, all players have the Navigation skill (based on
Memory). If you make your roll, you know where you are and know your way back
to town. If you make another Navigation skill check, you have followed an
ancient map to this level and get a mapping effect that reveals the nearby
dungeon.
