The story revolves around Rex 's attempt to stop villain Van Kleiss from threatening the Earth. Rex journeys through the game collecting or attempting to collect blueprints and evidence against Van Kleiss. Throughout the adventure, Rex must also work to regain powers lost from an event early in the game, and also absorbs the nanites in some infected people - many of whom have turned into monsters.
Rex 's powers include the Smackhands (giant robotic fists), Slam Cannon, BFS (Big Fat Sword), Funchucks (massive spinning club-fists inspired by nunchucks), and a few others. Many of them must be re-earned as the player progresses through the game. The gameplay typically plays as a beat-em-up, with brief breaks featuring stages with shooting-heavy driving, and a falling sequence where players dodge E.V.O. monsters and other debris.