minimal:
reqprocessor: Intel Core i5-750, 2.67 GHz | AMD Phenom II X4 965, 3.4 GHz
reqgraphics: 1GB NVIDIA 640 or better with driver version 352.21 or later
reqmemory: 4 GB RAM
reqdiskspace: 47 GB available space
reqsystem: Ubuntu 14.04.2 64-bit / SteamOS
reqother: AMD and Intel cards are NOT supported. If you wish to play the game using an AMD graphics card, you should update your graphics driver to version Catalyst 15.7 or higher. You should be able to run the game without experiencing stability issues or graphical glitches, but you may still experience poor performance.

recommended:
reqprocessor: Intel Core i7-3770, 3.4 GHz | AMD FX-8350, 4.0 GHz
reqgraphics: 4GB NVIDIA 9xx series card or better with driver version 352.21 or later
reqmemory: 8 GB RAM
reqdiskspace: 47 GB available space
reqsystem: Ubuntu 14.04.2 64-bit / SteamOS
reqother: Gamepad