The Amagon NES game, or simply "Amagon", is an arcade platformer developed and released originally in Japan and re-released for Europe and the US a year later.
The plot of the Japanese version of the game differs from that of the US and European versions. In the original Japanese version, the main character, scientist Jackson, crashes his plane and transforms into Machomen with a special drug. Some creatures stole his drug from the plane and the hero has to find the kidnappers and get out of the island. The Amagon version for the U.S. and Europe tells the story of a certain Marine who has to get away from a deserted island where he found himself because of a plane crash. As he collects power-ups, the Marine can transform into Amagon, a pumped-up and stronger character.
The main character is armed with a rifle that has a limited amount of ammo. You can replenish your arsenal by collecting bonuses from destroyed enemies. The enemies are various inhabitants of the flora and fauna of the island: snakes, bats, birds, etc. When transforming into Amagon, the character has super abilities, such as enhanced striking and firing energy waves.