The game uses a single-screen perspective. A formation of aliens moves horizontally across the playfield, shifts downward at each edge, and fires toward the player’s cannon.

Move the cannon left or right, fire upward, and use shields for temporary cover. Destroying aliens reduces the formation and usually makes the remaining invaders move faster. The objective is to clear the screen before the aliens touch the cannon’s level or the player loses all available lives. The cartridge includes several game variations that alter shields, firing behavior, and other rules.

Stay near the center until the formation becomes uneven, then move toward the side with the most dangerous remaining aliens. Clear the lowest invaders first because they are closest to the cannon.

Use shields selectively rather than hiding continuously; enemy fire and your own shots can wear them down. Fire at a steady rhythm, watch for openings between shots, and keep moving when the formation accelerates. In variations without dependable shields, prioritize survival and short controlled movements.