Street Fighter 2: The World Warrior by Capcom, the game that arguably put the Super Nintendo on the map for many gamers (I lived through it and remember the scene vividly). While the SNES was not exactly hurting without SF2, it was like night and day when SF2 was announced to be coming to the new Nintendo console- Sega, honestly, didn’t have anything to combat it (sure, eventually they had Eternal Champions but that was years later and against a pseudo-sequel of SF2).
The original Street Fighter 2 game only offered players eight characters to choose from (can you name all eight? Bonus points for the bosses too) to challenge the remaining seven combatants and four boss characters. What set SF2 apart from other fighting games at the time (Fatal Fury on the Neo Geo platform for example) is that SF2 offered the ability to create combos- the method of linking several moves together in an unblockable chain.
A fun tidbit for fans, the Super Nintendo version of the original Street Fighter 2 is the only home version of it. The Sega Genesis got a slightly renamed update that was similar to the version the SNES got around the same time (the Genesis version was actually delayed to coincide with the SNES version after rumored pressure from Nintendo on Capcom). We eventually did see home ports of the original SF2 on newer consoles but the SNES still holds the title of most versions of Street Fighter 2 for its generation.