In order for you to play Tower of Guns on macOS with minimal graphics settings, your computer must meet the following requirements
Operating System:
Mac 10.6 or later
Processor (CPU):
2.4 GHz Intel Core 2 Duo (Dual-Core)
Memory (RAM):
3 GB RAM
Graphics Card:
NVidia Geforce 275 GTX +512mb memory
Storage:
2 GB available space