In order for you to play SteamWorld Heist on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Steam OS 2.0 / Ubuntu 14.04 LTS
Processor (CPU):
2 GHz, SSE2 support
Memory (RAM):
1024 MB RAM
Graphics Card:
OpenGL 2.1-compatible, 512 MB video memory, framebuffer object support. E.g. Intel HD 4600 or better.
Storage:
320 MB available space
Sound Card:
OpenAL compatible
In order to play SteamWorld Heist on Linux with maximum graphics settings, you need a computer with a configuration no worse than the following
Processor (CPU):
2 GHz dual-core
Graphics Card:
Geforce GTX 660 / Radeon 7870 or better.