In order for you to play Slay the Spire on Linux with minimal graphics settings, your computer must meet the following requirements
Operating System:
Ubuntu 14.04 LTS
Processor (CPU):
2.0 Ghz
Memory (RAM):
2 GB RAM
Graphics Card:
1Gb Video Memory, capable of OpenGL 3.0+ support (2.1 with ARB extensions acceptable)
Storage:
1 GB available space