Visual: Fixed / flip-screen
Gameplay: Arcade, Shooter
Setting: Sci-fi / futuristic
Published by: Midway Mfg.
Developed by: Namco Limited
Platforms: Arcade Machine, Nintendo (NES)
Galaga is a fixed shooter game. The player controls the lone starship at the bottom of the screen, which must stop Galaga's forces from destroying all of humanity. The goal of each stage is to defeat all the aliens of Galaga, who are gathering in formation at the top of the screen. As in Galaxian, the aliens swoop down on the player while firing projectiles at the same time; colliding with projectiles or aliens results in loss of life.
At the top of the enemy formation are four large aliens, the "Boss Galaga", which require two shots to destroy. These aliens can use a tractor beam to take over the player's ship. Capturing a ship results in the loss of one life. If there are extra lives left, the player has the option to shoot down the Boss Galaga holding the captured ship. If it is shot down while it dives at the player, the captured ship will be saved and it will join the player's ship, forming a synchronized firing spark, respectively, the density of fire is doubled. However, if the Boss Galaga with the captured ship is destroyed while it is in service, the fighter will turn on the player and act as an alien.
Some enemies can transform into new types with different types of attacks, and one even takes on the form of a Galaxian flagship. Stages are indicated by emblems located in the lower right corner of the screen. As you progress through the game, the enemies become more aggressive, increase the number of projectiles and dive down at a greater speed. The third stage, and every fourth stage thereafter, are bonus stages in which the aliens fly in a given formation without shooting at the player.