In order for you to play XCOM 2 on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 14.04.2 64-bit or Steam OS
Processor (CPU):
Intel i3-3225 3.3ghz
Memory (RAM):
4 GB RAM
Graphics Card:
NVIDIA 650 (1GB), AMD R9 270 (2GB) or better
Storage:
45 GB available space
In order to play XCOM 2 on Linux with maximum graphics settings, you need a computer with a configuration no worse than the following
Operating System:
Ubuntu 14.04.2 64-bit or Steam OS
Processor (CPU):
Intel i7 series
Memory (RAM):
8 GB RAM
Graphics Card:
NVIDIA 960 (2GB)
Storage:
45 GB available space