Street Fighter II Turbo was like an early version of DLC, except you had to buy the game all over again! We were happy to do it, because that's how much better the new version of Street Fighter II was. This was a souped-up, deluxe version of the game that made the PVP fighting genre.
The hype for Street Fighter II Turbo was real. I got so excited when I saw it at my local Fred Meyer (a Pacific Northwest superstore) that I bought it instead of Final Fantasy II, which I'd been saving for. I quickly regretted this hasty decision and sold it to my friend, with whom I then played it more than I ever would have at home! Honestly, who ever plays Street Fighter II single-player!?
When the original Street Fighter II hit the SNES, the game had been in arcades for almost a year and a half, where it was an unrivalled powerhouse until Mortal Kombat arrived in late 1992. The Champion Edition (released in early 1992) added the four bosses as playable characters. This feature was absent from the SNES release, which was ported from the original. You can read my review of that version here, so I won't discuss the basic gameplay again. With Turbo, the third version of the game, Capcom had the chance to let players fight as Vega, Balrog, M. Bison, and Sagat in the comfort of their homes.
The main new feature is the titular Turbo speed. You can select the game speed on a scale of zero to three stars, with zero being the speed from the old version. Any higher speed makes the game more exciting. Playing on zero after getting used to a higher speed makes the game seem absurdly slow. For me, three stars is probably too fast, but you can go even higher: entering a code on the title screen with the second-player controller (↓, R, ↑, L, Y, B) lets you crank it all the way up to seven stars! At that level, the game moves hilariously fast and is barely playable. The ability to select the speed you want is an improvement over the arcade version, which plays at about two stars.
The main reason people were willing to shell out $80 (equivalent to around $170 today) for a game they already owned was so they could play as the powerful bosses. That wasn't the only reason: to keep the original characters competitive, each received a new special move (except Guile, who was already very good). Blanka and E. Honda gain a vertical charge attack to complement their horizontal one. Chun-Li is greatly improved because she gets a blue fireball (Kikoken). Dhalsim gains the ability to teleport (though it's difficult to perform). Ken and Ryu can now perform their spinning kick attack (Tatsumaki Senpuukyaku) while in the air. Finally, Zangief gets two new grapples, a suplex, and a professional wrestling throw called a Thunder Fire Powerbomb!
And that's pretty much it. There may be minor improvements, such as balance changes or improved sprites, but if they exist, they aren't noticeable to the average player. This is the same Street Fighter II we knew and loved, but at last we could play as the four bosses. And the characters had new moves! And we could crank the speed to whatever we wanted! In 2023 it would be outrageous to release a new version of a game at full price, but it was a different world in the early 90's. And, frankly, Street Fighter II was so good and so popular Capcom could get away with it. Once you play Turbo, it's unthinkable to go back. The original was completely obsoleted and worthless.
I still like Street Fighter II, but it's not something I play because it's not very fun as a single-player game. It's a PVP game, period. The story mode is all right and does have eight difficulty levels, which is good since the arcade version is quite hard. But this is a game for beating up on (or getting beat up by!) your friend. Nowadays you can play random opponents on the internet through the 30th Anniversary Collection.
"The original game was refined and improved; you could finally play as the four boss fighters and the additional speed injection made things much faster and enjoyable."
— Damien McFerran, Nintendo Life, 8/10
"Street Fighter was truly the beginning of a huge boom for the fighting game genre, and a trailblazer for dozens of other franchises."
— IGN, #6 of Top 100
"Street Fighter II: Turbo is the definitive 16-bit console version for the original, non-Super version of the game."
— Pat Contri, Ultimate Nintendo: Guide to the NES Library, 5/5