Battle Unit Zeoth is a 2D futuristic side-scrolling shooter where humanity faces an alien threat in the form of the "Grein". These robots invaded the Solar System two years after their initial attack. The humans have developed a special mech, Zeoth , to combat them.
The player controls Zeoth as it moves to the right and shoots enemies. The game is divided into odd-numbered stages with horizontal scrolling and even-numbered stages with simple platform elements. Each stage ends in a boss fight. Zeoth can fly using a jetpack, but the player must press a button to counteract gravity. It also has four directional firing options: right, left, down, and up. The basic weapons can be upgraded.
Battle Unit Zeoth was released on Game Boy in 1970 and is classified as a Shoot'em Up game. The player must guide Zeoth through six stages, each with its unique challenges and enemies to defeat.