Alphaman is a free, independently made post-apocalyptic roguelike game produced in 1996, by Jeffrey R. Olson. Its an adventure/survival RPG with some odd humor added, and is based on the rules of the first edition Gamma World tabletop role-playing game. You play as a humanoid mutant, with randomly generated stats, and random mutations and equipment at the start of the game. Your goal, is to locate Grinch's stronghold and defeat him before he unleashes a weapon that would end all life on earth. Along the way, you fight mutants and robots, explore old ruins and bunkers, and find technological artifacts. Artifacts must be examined before they can be used, and they often have uses that are not always apparent (but can be funny or surprising).
Source: The Developer Website.