The Playstation version of X-Men Vs. Street Fighter was released in 1998. Due to RAM limitations of the hardware, this port had to be cut-down to never before seen levels, making the Playstation port of Marvel Super Heroes look quite good in comparison. The major cut from this version is the tag team option -the main feature of the game -as whilst you can select two characters, you cannot swap between them during a fight. Instead, the second character will only appear during team hyper combos and tag counters. Due to this, the Playstation version features a best 2 out of 3 rounds system, seen in most other fighting games. Vitality recharging was also changed for this version, as you now have to just try and avoid taking hits for several seconds to get the red part of the vitality gauge to turn green.
The graphics also took a hit, with many frames of animation removed. Certain special attacks are now choppy, such as Juggernaut's punch. The idle stances for each character also had many animation frames removed, and some characters, like Cyclops, look weird and awkward. Some background details were also simplified, such as the police car sirens on the Manhattan stage having less animation frames than in the arcade version.
It isn't all bad news though, as the Playstation version is the only one which lets you play as Apocalypse without resorting to hacking. There are also training and survival modes exclusive to this version, but in the end, if you want to really play X-Men Vs. Street Fighter on a console, you'll need to get the SEGA Saturn version.