Gungame is a game about guns. More specifically, it's a game about a glowy circle on a constant quest to upgrade its guns. You guide your glowy circle around a 2D grid, eating dots and getting bigger. Every dot you eat allows you to upgrade your weapon and stocks up your ammo. Every shot you fire makes you smaller and depletes your ammo. The more upgraded your gun is, the easier it is to shoot other glowy circles.
WASD to move, Shift to sprint. E to upgrade your gun. Aim with the mouse and shoot with a left click. You get bigger as you eat the glowing dots and smaller as you upgrade or fire your weapon. Your goal is to be the biggest glowing circle on the field.
Upgrade your weapon until it is one that allows you to shoot backwards or shoot a heat-seeking round. This will definitely give you an offensive advantage. If you are just looking to get bigger, float around the peripheries of the map.