The objective of Galaga is to score as many points as possible by destroying insect-like enemies. The player controls a starfighter that can move left and right along the bottom of the playfield. Enemies swarm in groups in a formation near the top of the screen, and then begin flying down toward the player, firing bullets at and attempting to crash into them. In later stages, some enemies even break from an entering group in a frantic attempt to crash into the player. The game ends when the player's last fighter is lost by colliding with an enemy, being hit by an enemy shot, or being captured.
A "hit/miss ratio" statistic at the end of the game, and a bonus "Challenging Stage" that occurs every few stages, in which a series of enemies fly onto and off the screen in set patterns without firing at the player's ship or trying to crash into it. When you destroy a group of enemies, you are awarded 1500 points.These stages award a 10K-point bonus if the player manages to destroy every enemy, but otherwise 100 bonus points for every enemy destroyed. Another feature in the game is for enemies to randomly transform and organize into a certain formation, which awards the player bonus points if they manage to successfully destroy it.
Another gameplay feature new is the ability for enemies to capture the player's fighter. While the player is in control of just one fighter, a "boss" Galaga (which takes two hits to kill, the first hit will turn it purple) will periodically attempt to capture the fighter using a tractor beam. If successful, the fighter joins the enemy formation as a satellite to the boss Galaga which captured it. The captive fighter becomes an enemy, turns red, and likewise, it can be shot and destroyed. The player can still fire while being captured up to the point their ship "touches" the captor, which could be considered an opportunity to shoot the captor down before it can manage to successfully capture the player. Captive fighters can be freed by destroying the boss Galaga towing it while it is attacking. The freed fighter will then combine with the player's fighter who freed them, offering doubled firepower but with the disadvantage of a target twice as large. If the player destroys the captor while it is still in formation, the captured fighter will not be rescued, and will instead fly away after a diving run (assuming the player does not destroy it) to appear in the next stage as a satellite for another boss Galaga where it can again be rescued.
*Notice: This game doesn't support Android 8.0+