Set a century after the events in the original Mega Man series, Irregular Hunter X is a remake of the original SNES game Mega Man X, and details the story of Dr. Light's greatest creation: X, a robot with free will. Dr. Cain's discovery of X led to the creation of reploids, robots modeled after the design of X. When the maverick virus infects a group of reploids, they band together in a revolt against humanity. The call goes to the maverick hunters, X and Zero, to fight the Mavericks.

The game is a side-scrolling action game where the player controls X as he hunts the maverick reploids. Notable features include the ability to find enhancements to augment X's abilities, and the ability to absorb the powers of the maverick reploids X defeats. The original moves, such as dashes, wall jumps and charge shorts are still present.

The original flat backgrounds have been replaced by polygonal models, and the remake features enhanced explosions and generally more detail. Additionally, animated cutscenes and voice acting have been added. All weapon and armour upgrades have been relocated to new hidden areas, and there is a new mode: Vile, in which you can play the entire game as maverick Vile, with abilities Mega Man does not have. As a bonus, there is a demo of Mega Man Powered Up on the UMD - a remake of the very first Mega Man game.