Windows
MINIMUM:
OS: Windows 7 64Bit
Processor: Intel® Core™ 2 Duo 3.0Ghz
Memory: 3 GB RAM
Graphics: (DirectX 11) AMD Radeon HD 5770 1024MB | NVIDIA GTS 450 1024MB | Intel HD4000 @720P
DirectX: Version 11
Storage: 35 GB available space
Additional Notes: *PC Integrated graphics chipsets require 4 GB RAM, e.g. Intel HD series.
Mac
MINIMUM:
OS: macOS 10.12.4 (10.13.6 Recommended)
Processor: 2.0Ghz Intel Core i5
Memory: 8 GB RAM
Graphics: 2GB Nvidia 680MX, 2GB AMD R9 M290, 1.5GB Intel Iris Graphics 540 or better (see notes for more details)
Storage: 37 GB available space
Linux
MINIMUM:
OS: Ubuntu 16.10 64-bit, SteamOS 2.0
Processor: 3.4GHz Intel Core i3-4130, 3.5GHz AMD FX6300
Memory: 4 GB RAM
Graphics: 1GB Nvidia 650ti or better (driver version 367.28), 2GB AMD R9 270 or better (Mesa 13.0.1 driver compiled using LLVM 3.9)
Storage: 29 GB available space
Additional Notes: AMD GPU's are not supported on Steam OS. Intel GPU's are not supported at time of release.