Cannon Fodder gives the player direct, physical control over a virtual cannon with which to shoot attacking goblins. The goblins pass between two cannons (for two players) and try to reach the castle. After a certain number of goblins reach the castle the game ends.

Players aim the cannons by moving and rotating the cannon towers. The cannon is then charged by obscuring the glyph with a hand. While the glyph is covered, crosshairs move out from the cannon. When the crosshairs are in the desired spot, players remove their hands to fire.