In Heavy Weapon, the player guides a powerful atomic tank through level after level of opposing enemy forces. The tank moves only left and right, while its main weapon, a turret gun, can be aimed up and down at various angles. The game's storyline deals with a Red Star (Soviet Union) invasion, and the player takes the role of the commander of an Atomic Tank to repel the invasion back into the main headquarters of Red Star. The main premise of the game is one individual against the collective forces of Communism.
The game features a total of 19 levels/missions and two game modes (mission and survival). In mission mode, one must blast through countless enemies and defeat a boss at the end. Mission mode allows for three lives each mission. Upon defeating the boss, the player visits the armory, where one can get various upgrades and power-ups for use in subsequent missions.
Source: Wikipedia, "Heavy Weapon", available under the CC-BY-SA License.