Andro Dunos is a horizontal-scrolling shoot'em up that takes place during an alien invasion. The player must navigate through seven stages, fighting their way through enemy ships to reach the heart of the base and defeat a boss at the end of each stage.
Gameplay involves switching between four main weapons, which can be upgraded with power levels. Players can also use charged shots, which are more powerful but require holding down the fire button for two seconds. Losing all lives forces the player to restart from the start of the second weapon level and lower sub-weapons.