Galaga '88 builds upon the original GALAGA '88 's gameplay with enhanced graphics, triple ship abilities, parsec progression, power-ups, asteroids, bosses, and other improvements. Players must shoot all 40 enemies on screen before they disappear to receive a bonus of at least 10,000 points. The game features a total of 29 stages, allowing players to choose between starting with one ship and two reserves or beginning with a dual ship.
The gameplay is filled with challenging enemies that have unique behaviors. Some combine into larger enemies that require multiple shots to destroy, while others explode in fireworks when hit, releasing smaller enemy formations. Certain creatures take multiple hits before being destroyed and emit loud noises when hit.
Some enemies have armor that makes them invincible during formation, but they become vulnerable for a brief period, allowing players to destroy them with one hit for bonus points. Obstacles such as blue crystals, boulders, and green blobs also appear throughout the game, adding to the challenge.