In order for you to play Valhalla Hills on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 15.04 (64 bit only)
Processor (CPU):
Dual-core Intel or AMD, 2.5 GHz or faster
Memory (RAM):
4 GB RAM
Graphics Card:
NVIDIA GeForce 8800 GT or Radeon HD2900 series card or better (DirectX10 card or better)
Storage:
3 GB available space
Sound Card:
Sound Card with Latest Drivers