When trying to run Duck Game on Linux natively with XnaToFna, Duck Game will try to access the Steam API (Steamworks) through its Steam.dll. The only issue with that is... that it's a mixed-mode assembly, thus restricted to Windows. Furthermore, it's restricted to x86, which isn't that horrible for XNA games, but FNA supports making use of all 64 bits in your CPU(tm).

This Steam.dll replacement just tries to "proxy" any Steam.dll calls to Steamworks.NET, which supports all Steam platforms: x86 and x64 Windows, Linux and macOS.

• When using XnaToFna, you'll need to pass -nothreading -nomods.
• On Linux, Duck Game will complain about missing paths as it forgets to create the save profile directories. Currently working on a separate fix.
• It's not a complete replacement yet, it'll be outdated with future Duck Game updates and I'm stuck on a 1G connection right now, which makes testing this a pain in the a~
• You need to copy the proper files from the Steamworks.NET directory to the Duck Game directory. For Linux, you need to rename Steamworks.NET-linux.dll to just Steamworks.NET.dll. The x64 variants of steam_api and CSteamworks are supplied.
• You should be able to use a stubbed Steamworks.NET to get Duck Game running "DRM-free" on non-Windows platforms. I've uploaded one for FNADroid, it should just work(tm): https://github.com/0x0ade/FNADroid/blob/master/FNADroid/libs/managed/Steamworks.NET.dll