In order for you to play Shelter 2 on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 12.04
Processor (CPU):
Intel Core 2 Duo E4500 @ 2.2GHz or AMD Athlon 64 X2 5600+ @ 2.8 GHz
Memory (RAM):
2 GB RAM
Graphics Card:
GeForce 240 GT or Radeon HD 6570 – 1024 MB (1 gig)
Storage:
2 GB available space
Sound Card:
OpenAL Compatible Sound Card