In order for you to play Sheltered on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
10.8.5
Processor (CPU):
Dual Core CPU or higher
Memory (RAM):
2 GB RAM
Graphics Card:
Nvidia GeForce GT 330M, AMD Radeon HD 5750M, Intel HD Graphics 4000 or above
Storage:
700 MB available space