Dig Dug

Dig Dug is a maze video game where the player controls the titular protagonist, Dig Dug (Taizo Hori), to eliminate each stage's enemies: Pookas , red and spherical beings that wear comically large goggles ; and the draconic Fygars, which breathe fire. Dig Dug can use an air pump to inflate them until they explode or crush them to death under falling rocks. When the air pump is activated, Dig Dug will stop moving and throw the end of the air pump forwards, where it may catch onto an enemy. If an enemy is hit, they are frozen in place and the player can repeatedly press the air pump's button to inflate them.

If no action is taken for a while or the player moves, the air pump disconnects and the action is cancelled, but the enemy will begin to deflate and will be stunned until fully deflated. Rocks are unable to be dug through but will fall after a short period of time after the tile directly beneath them is removed by Dig Dug and he moves from the position, though he can still be crushed. Falling rocks are destroyed once they land on a tile. Bonus points are awarded for squashing multiple enemies with a single rock and dropping any pair of rocks in a stage yields a bonus item, which can be eaten for points, and increases its point value the further the player gets in the game.

Once all the enemies have been defeated, Dig Dug progresses to the next stage. Enemies can move through tiles, where they are represented in the form of ghostly eyes, and are invulnerable, slowed and unable to attack, and will then return to being solid once in an empty space, whether that space is their destination or is along the way. The enemies can either do this to reach Dig Dug when they would otherwise be unable to or to escape from the stage as the last enemy. As enemies are defeated, the enemies eventually become faster and more aggressive, until the last one then attempts to escape on either side of the screen at the top of the stage.

To escape, enemies will move straight up through any tiles before walking towards the nearest screen edge on the surface. The game has 255 stages. Later stages vary in dirt color, while increasing the number and speed of enemies. Lives are lost upon touching a foe, Fygar's fire or getting squished by a falling rock, but players are given extra lives during the game.

At round 256, the game experiences an 8-bit integer overflow bug and attempts to instead load round 0. Doing so causes level generation to misbehave, and the game spawns a Pooka inescapably on top of Dig Dug, draining the player of all their lives and ultimately ending the run. This kill screen is the ending of Dig Dug in most versions of the game, but a later Atari release patched this bug and instead allows infinite play.