Amagon is a side-scrolling platform action game, which was developed for the NES by Aicom.
In this game, the player controls Amagon, a Marine who is trapped on an island after his plane crashes.
Inconveniently, his rescue ship is on the other side of the island, so Amagon must cross the island on foot to save himself. While on his journey, he encounters a variety of enemies which he must defeat. Initially, Amagon can equip a gun, but he later gains the ability to transform himself in to a larger, stronger alter-ego called "Megagon".
Upon transformation, Megagon can no longer use the machine gun, but instead is able to punch, and fire waves of energy from his chest which can hit multiple enemies in a single blast.
The game features 6 zones of 2 stages each. An alien boss appears at the end of each zone.