AD Infinitum is a side view single screen shooter where you control a spacecraft that can move around the screen in various directions blasting waves of aliens over 256 levels. Each wave of aliens appear from various places on to the screen and drop bombs as they move and if you are hit by a bomb or alien then you lose one of six lives but you have six continues to use when your lives are gone. As you fire your weapon, a gauge increases showing it overheating and if the gauge fills then you also lose a life. Moving and firing around the screen also decreases a fuel gauge and when this empties then a life is also lost but fireballs can be touched to increase it. They appear when an asteroid storm moves down the screen and the asteroids have to be avoided as well. After so many levels your Mothership appears at the top of the screen and you must dock with it to receive a fuel bonus. Up to four players can play and each player takes it in turns to play when the other players have lost a life.