In order for you to play Monster Sanctuary on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 14.04
Processor (CPU):
Dual-Core, 2.0 GHz
Memory (RAM):
2 GB RAM
Graphics Card:
GeForce 8800 GT 512 MB, Radeon HD 4870 512 MB
Storage:
1 GB available space
Sound Card:
DirectX Compatible Sound Card