X-Men vs. Street Fighter is a 2D tag-team fighting game developed and released by Capcom for the arcades (under the CPS-2 engine) on October 4, 1996. The first installment of the long-running Marvel vs. Capcom crossover series, the game pits fighters from X-Men: Children of the Atom with the fighters from Street Fighter Alpha 2, in a fast-paced high-flying tag team match. Using the "Variable" system, players can tag in their backup character (either on-the-fly or as a counter-attack) or perform a special "combination" attack (in which both characters perform their Hyper Combos simultaneously).
The game was ported to the Saturn (in Japanese regions only) on November 27, 1997 and PlayStation on June 30, 1998. While the Saturn version retains all animations and the tag-team mechanic of the arcade version (thanks to the 4MB RAM expansion cartridge), the PlayStation version removes the tag-team mechanics for normal gameplay (restricting it to traditional 1v1 round-based fights, in which the secondary character plays an "assist" role), adding a new "Crossover Mode" (in which the tag-team mechanic is brought back, but each player's secondary character is the opposing player's primary character).
X-Men vs. Street Fighter uses very similar gameplay style that was developed in Marvel Super Heroes, and also adds the tag team feature. The game doesnt use the regular three round format, but each player has two characters, controlling one at a time, while the other character waits off screen. The player can tag the waiting character in at any time by pushing the hard punch and hard kick buttons at the same time, which then activates what is known as the "Variable Attack", with the character jumping in with an attack and briefly taunting. During the character taunt, they are open for a counter attack. The character now off screen with recover a small portion of their vitality, with the current character now fighting. When one character dies, the other character will automatically be tagged in, and when both characters have died, the match is then over.
There are different ways to bring the other character in; such as the "Variable Counter", which replaces the Infinity Counter from Marvel Super Heroes, breaks the opponents guard to then bring the teammate in with a counter attack while using some of the super meter. There is also the "Variable Combination", which is a two-character Hyper Combo (the super moves in the game) which drains two levels of the super meter, and will then switch the player's current character as long as neither character gets hit during their Hyper Combos.
Most of the X-Men characters are from X-Men: Children of the Atom and Marvel Super Heroes, with three new additions being Rogue, Sabertooth and Gambit. The Street Fighter characters use their forms from Street Fighter Alpha 2 with their special moves getting upgrades to match the over-the-top Marvel games (example being, Ken's Shoryuken makes him flame up and hit his opponent very high). This game gives the first appearance of the "Shadaloo" version of Cammy, who would then be used later in Street Fighter Alpha 2 Gold and Street Fighter Alpha 3.
X-Men vs. Street Fighter includes 17 playable characters (eight from X-Men side and nine from the Street Fighter side). The game also includes an unplayable boss, Apocalypse, who takes up much of the screen and does not have a tag partner. After defeating him in single-player, the player is forced to fight his/her teammate to show the player-controlled character's ending.
All characters are from X-Men: Children of the Atom, with the exception of Gambit, Rogue, Sabretooth, and Apocalypse.
All characters are from Street Fighter Alpha 2, with the exception of Cammy.