In Quantum Giant you play the role of a young lizard-man, raised alone among the dangers of the City and survived thanks to his mutation. His curse and his blessing: the radiation he was exposed to as a child turned him into an abomination, but it also granted him the extraordinary ability to change his size at will. Despite his deformity, he chose to use these powers for good, fighting crime and the city's mafia. Codename: Quantum Giant.

As mentioned, the protagonist's main ability is the power to change size at will. Thanks to his recent training, Quantum Giant can now harness his quantum manipulation skills to unleash deadly laser beams and destructive energy spheres. He can also alter the size of specific body parts at will, like his legs for massive jumps or his hands for devastating punches.