itch.io

The free version is version 2.0 which doesn't have official mod support

3.0 has mods support! Buy it on Steam :)

Well now there is a Linux version for 3.0, try installing it from Steam!

I tested the OpenGL version of the 2.0 release on Arch with WineHQ installed, and it worked like a charm! You should give it a try maybe (didn't try 3.0 for now sorry about that)

Edit: Apparently there is a Linux version for 3.0 lol, my bad (2.0 doesn't have any though)