A Game Boy Advance version, titled Final Fight One, was released in 2001. This version was based on the previous SNES versions (particularly Final Fight Guy), but contained all three playable characters and co-op gameplay through cable linking. The missing Industrial Area stage was restored as well, with the second Bonus Round moved after the fifth stage (the Bay Area). The Guy/Haggar and Jessica doll power-ups were kept, with a Cody doll added to the mix. Most of the scene transitions were added to this version, though a few are still missing such as boarding the train in mission 2 (the doors of the train also do not open as they do in the arcade) and entering the lift in the final mission.

A feature unique to this version, is the added dialogue between the main characters and the enemies prior to boss fights. Sodom and Rolento are shown in their win pose from Street Fighter Alpha 3 when introduced. The game also allows the player to play as the Alpha versions of Cody and Guy after defeating a determined amount of enemies with the regular version of the characters. (Wikipedia)

Unlockables

Unlock Alpha Cody
To play Cody with his alpha sprite, simply defeat 500 villains and he will become selectable.

Unlock Alpha Guy
To play as Guy with his alpha sprite, simply defeat 50 villains and Alpha Guy will become selectable.

Unlock Secrets
As you progress through the game you will earn fighting points. These points go towards unlocking secrets in the game itself. If you want to unlock everything you will need 2000 points. Here is the order that the secrets are unlocked:

Extra Lives: This allows you to have 9 lives.

Stage Select: You can choose from level 1 to level 6.

Color Change: Changes character color and unlocks Alpha Guy and Alpha Cody.

Rapid Punch: Now you can simply hold the punch button and you will punch rapidly.

Third round of pain for the Final Fight brawlers: