Featuring ten tanks from World War II, Mobile Armor is a mission-based shooter in which you control the "Mars army tank" in battle against a succession of "Earth army tanks." Completed missions in single-player story mode become available for two-player free mode, with one player manning the cannons and the other the tank, as well as for two-player VS mode. In VS mode, five tanks are available from cleared story mode missions, with another five added based on the number of cumulative defeated Earth army tanks.

Tanks are rated in speed, range, power, energy, armor level, and recovery ability, and can be upgraded with generic equipment such as a Hyper Engine, L-Range Unit, Armor A, B, and C, Super Cannon, and Spare Energy. In-game screen displays show radar, opponent's tank, speed gauge, energy gauge, lock-on sights, armor level, and movement. Damage is calculated based on the distance between combatants. Closer shots are more damaging but being too close or behind a wall may actually prevent a shot.