Yes, not .NET support for the moment.
This has a winforms launcher that works with wine-mono, but in my local build (4.2-ish), it suffers from rendering issues in-game.
Game starts fine for me with 4.11-2. Launcher shows up and works, game itself launches, at least I see its menu. @llikeitt please retest with 4.11-2.
Nothing extracted yet.
Steam - System Information
steam-477730.log (launcher.exe)
I think it is related to the Microsoft .NET Framework which not work in an 64bit PREFIX?