Street Fighter II Black Belt Edition, sometimes referred to as Rainbow Edition, is probably the most famous hack of the game due to it appearing in many American and European arcades. This hack changes a lot of things in the game. All special moves can now be done whilst jumping, and you can now also have multiple projectiles on the screen at once. So Ken can throw out several projectiles without problem and Guile can do his sonic booms in the air, for example. The speed of all projectiles has been changed, as the jab punch versions are really slow, whilst the fierce punch versions are incredibly fast. The strong punch versions can actually lock onto the opponent (!) whilst moving pretty quick.
Certain characters, like Honda and Zangief, can now move much faster, and there are a lot of moves that release hadouken projectiles, such as Vega's roll. When fighting the CPU, your opponents will often change to a different character when hit. You can also change characters yourself by pressing the start button.
Certain things in this hack inspired Capcom when they made Street Fighter II' Hyper Fighting, such as the fierce punch version of Blanka's cannonball moving up into the air which can hit jumping opponents. In Hyper Fighting, Blanka was given a new move when he rolls upwards to hit airborne opponents.