Galaga

The objective of Galaga is to collect as many points as possible by destroying insect-like enemies. The player controls a starfighter that can move left and right at the bottom of the screen. The enemies swarm in groups in a formation at the top of the screen, then fly toward the player and fire bombs at the space fighter. The game ends when the player's last fighter is lost, either by colliding with an enemy or one of its bullets, or by being captured. Galaga introduces a number of new features compared to its predecessor Galaxian. These include the ability to fire more than one bullet at a time, a count of the player's "hit rate" at the end of the game, and a bonus "challenge phase" that occurs every few levels in which a series of enemies fly in and out of the screen in specific patterns without shooting or attempting to collide with the player's ship. In these stages, there is a large points bonus if the player manages to destroy all the enemies. Another new feature in Galaga is the ability for enemies to capture the player's space fighter. While the player controls only one fighter, a "boss Galaga" (which can be killed with two shots) periodically tries to capture the fighter with a tractor beam. If he is successful, the fighter joins the enemy formation. If the player still has more lives, the game continues with a new fighter. The captured space fighter flies with the enemy that captured it and fires at the player like normal enemies and can be shot down and destroyed. The player can free the fighter by destroying the boss Galaga while it is flying. This causes the captured fighter to link up with the player's current fighter, doubling its firepower but also creating a target that is twice as large. Galaga has an exploitable bug that can cause the attackers to stop firing at the player due to a programming error. Also, similar to the famous "split-screen bug" in Pac-Man, Galaga has a bug where the game "rolls over" from level 255 to level 0. Depending on the difficulty of the device, this can cause the game to stop and the device to have to be reset or turned off to start a new game.