Target Earth is a space shooting game set in the future where Earth is under attack by robots. The protagonist of the game is a pilot of a mech robot that can move between planet surfaces and space. There are two types of levels in the game: surface levels take place on planets or moons, allowing the mech to run and jump to the end of the level while fighting enemies. Space levels have no gravity and allow the mech to move in any direction.
The gameplay involves flying through levels and shooting down enemy robots with various machine guns, lasers, and grenades. The player must navigate through increasingly difficult levels, using their wits and reflexes to avoid enemy fire and destroy targets. As players progress through the game, new enemies are introduced, and the level of difficulty increases.