X-Men vs. Street Fighter

X-Men vs. Street Fighter is a crossover fighting video game developed and published by Capcom. The game includes characters from Marvel's X-Men franchise and the cast from Capcom's Street Fighter series.

X-Men vs. Street Fighter features gameplay similar to Street Fighter, but incorporates dual-character selection and tag team-based combat. Each player selects two characters to compete in a one-on-one battle, attempting to defeat the opposing team. The players are given the ability to switch between their characters at any point during the match. The game also incorporates numerous elements from X-Men: Children of the Atom and Marvel Super Heroes.

Similar to Capcom's various Street Fighter titles, X-Men vs. Street Fighter is a 2D fighting game in which players control various characters to engage in one-on-one combat, attempting to knock out the opponent by depleting their health. It is the first formal installment in the Marvel vs. Capcom series and features dual-character selection and tag team battles. Instead of the typical best-of-three round format, matches consist of a single round.Players select two characters at the beginning of a match, each sporting their own life gauge. Players control one character at a time, while the other awaits off-screen. The starting character can tag in the off-screen character at any time during the fight. The dormant character will also slowly recover a portion of their vitality while the current character is fighting. If one character loses all of their vitality, then the tag partner will automatically come into play. The match continues until both characters on either team are defeated. If the timer runs out before either team is knocked out, then the player with the most combined remaining health is declared the winner.

Source: https://en.wikipedia.org/wiki/X-Men_vs._Street_Fighter