Street Fighter II Turbo

The 1992 update that turned Street Fighter II from a great game into the fighting game. Turbo added speed settings, let you play as the bosses, and balanced the roster just enough that tournaments still had variety. It single-handedly built the competitive fighting game community and the arcade scene of the '90s. The hadouken motion is muscle memory for an entire generation. Modern fighters like Street Fighter 6 are still iterating on the template Turbo perfected.