Originally released as The Sacred Armour of Antiriad in the UK by Palace Software. It was later released in the US by Epyx as Rad Warrior.
The game takes place in the year 2086 after a nuclear apocalypse caused by two warring factions. Soon after the war an ancient breed of aliens arise from a military base within an old volcano and enslave the human race. The player controls the games protagonist Tal who is tasked to seek out the Sacred Armour of Antiriad and defeat Earth's new alien overlords. Throughout the game Tal gathers upgrades for his suit including those that allow it to fly, shoot and drop mines, eventually defeating the Earth's alien inhabitants.
Rad Warrior was released only a month after the initial Japanese launch of Metroid and contains many similar features. Despite the similarities between the two games it is generally believed that due to the long development cycles and separation of the two games this was due to mere coincidence.