Galaga is a fixed shooter in which the player controls a space fighter positioned along the bottom of the screen. The objective is to destroy every enemy in each stage while avoiding projectiles and diving attacks. Enemies enter from the top and sides, assemble into a formation, and then break away to attack. There is no story campaign or character progression; the game continues through increasingly difficult stages until all remaining fighters are lost.

Enemy Formations and Attacks

Enemies are divided into Grunts, Guards, and Boss Galagas. Regular enemies can be destroyed with one shot, while Boss Galagas require two hits. Shooting enemies while they are diving can award more points than destroying them in formation. Later stages increase the speed and frequency of attacks, making it harder to remain in a safe position near the bottom of the screen.

Tractor Beams and Dual Fighters

Boss Galagas can stop during an attack and activate a tractor beam. If the player’s fighter enters the beam, it is captured and carried into the enemy formation. With another fighter, the player can shoot the Boss Galaga while it is diving and rescue the captured ship, creating a Dual Fighter. This doubles firepower but also makes the player’s ship wider and easier to hit.

The main actions and objectives include:

·         moving the fighter left and right;

·         firing at enemies above the player;

·         avoiding enemy bullets and diving aliens;

·         destroying the entire formation to clear a stage;

·         rescuing captured fighters to gain Dual Fighter mode;

·         earning points by destroying enemies and completing bonus stages.

Every third stage is a Challenging Stage. Instead of attacking the player, groups of enemies fly across the screen in preset patterns. The goal is to shoot as many as possible before they leave, and clearing all targets awards a large bonus. These stages also make Dual Fighter mode particularly useful because two simultaneous shots cover more of the screen.

Controls and Long-Term Progress

The controls are limited to horizontal movement and firing. Clearing all enemies advances to the next stage, while losing every available fighter ends the game. Extra fighters can be earned by reaching certain score thresholds, and the final score also reflects how many enemies were destroyed and how accurately the player fired. Galaga has no conventional final level in normal play, so progress is mainly measured by surviving farther, reaching higher stages, and improving the score.