Megamania is a classic Atari game similar to that of Space Invaders. The player controls a ship at the bottom of the screen and can move the ship left and right with the joystick. The button fires the ship's guns upward to attempt to eliminate all the enemies in order to move on to the next stage.
Each stage has a different set of enemies that moves in a different pattern (and at varying speeds). The enemies include a wide range of odd things as bugs, diamonds, irons, and space dice. The enemies also shoot down at the player's ship which will explode if hit. The player gets 3 ships and the game ends once they all explode. The player can also blow up if an enemy comes in contact with the player's ship.