(Unverified) You must finish the entire game. Alternately, defeat the boss porno guy in the warehouse when he's using the forklift truck to kill you. Defeating him unlocks the original Final Fight in the Bonus menu.
Unlockable: Guy
In Story mode, get out of the burning dojo alive.
Unlockable: Hagger
In Storyline mode, you must meet Hagger.
Unlockable: Japantown
Finish minigames. Then talk to the shopkeeper of the Flesh Scrawl Tattoo Parlor.
Unlockable: Little Italy
Enter Little Italy for the first time.
Unlockable: Pier District
Enter the Pier District via the train in the Subway following the cutscene with 2-ill.
