FYI, the game requires OpenGL 4.3 [1] (the porters have mentioned compute
shaders specifically [2]), so it *can't* work with radeonsi yet.

[1] See the Linux system requirements on
http://store.steampowered.com/app/214490/
[2] https://www.reddit.com/r/linux_gaming/comments/3t5p0r/a/cx3hn8i