Tetragun is a top-down shooter where you play as a stationary turret and defend yourself against waves of enemies. As you progress through the waves, you will acquire upgrades to help you keep up with the growing strength and numbers of your enemies. The arena is split into 4 quadrants, and your turret will only be able to aim within the confines of the quadrant it is currently in. To aim at enemies outside of your current quadrant, you'll need to enter rotate mode with RMB and click on the quadrant you would like to rotate to. The goal of the game is to make it as far as possible, and get the highest score you can.