X-Men Legends is an action role-playing game. Players choose a team of up to four characters from a larger group of X-Men. As players proceed through the game, additional X-Men are unlocked. On the console versions, up to four players can play in the cooperative campaign, with the ability to add or remove players at any time.[4] Cooperative play features a refined combat system and the ability to interact with non-player characters. The game also features a skirmish mode, which allows players to fight against each other or against waves of computer-controlled enemies.[4]
As characters gain experience points, players can upgrade their four main powers and other abilities unique to that character. Items found during gameplay can also be equipped to further enhance a character's abilities.[4] Characters can combine attacks to create a combo, in which two or more players use their mutant powers on a single enemy at the same time. The characters' special abilities can be used to create a "Super Combo" when combined with an "Xtreme Power" which become available at level 15.