300 years have passed since humanity's great war left the world in ruins. Small groups of survivors live on in the wasteland, but mysterious towers have appeared, emitting a deadly diablosis that corrupts anyone who touches it. These towers seem sentient, and anyone who approaches will meet a deadly end.
Quantum Theory is a third-person shooter where Syd, a lone warrior, must destroy the towers and stop the diablosis. The game features cover-based shooting, allowing Syd to hide behind cover and fire from safety. He can also perform a "roadie run" to quickly move between cover or engage in melee combat with powerful attacks. Syd can team up with Filena, performing special team attacks, and even throw her at enemies for added power. The game includes a single-player campaign and online multiplayer modes.