In order for you to play SteamWorld Dig on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
10.7
Processor (CPU):
2 GHz
Memory (RAM):
512 MB RAM
Graphics Card:
OpenGL 2.1-compatible, 384 MB video memory, framebuffer object support
Storage:
120 MB available space
Sound Card:
OpenAL-compatible