In order for you to play Outlast on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 12 / Fedora 20 / Steam OS
Processor (CPU):
2.2 GHz Dual Core CPU
Memory (RAM):
4 GB RAM
Graphics Card:
GeForce GT 750M / 9800GTX / Radeon HD 3xxx. OpenGL 3.2+
Storage:
5 GB available space
Sound Card:
Standard
In order to play Outlast on Linux with maximum graphics settings, you need a computer with a configuration no worse than the following
Operating System:
Ubuntu 14 / Fedora 21 / Steam OS
Processor (CPU):
2.8 GHz Quad Core CPU
Memory (RAM):
4 GB RAM
Graphics Card:
1GB NVIDIA GTX 460 / ATI Radeon HD 6850. OpenGL 4.x+
Storage:
5 GB available space
Sound Card:
Standard