At the title screen, select Password, then enter this: A5, B2, B4, C1, C3, C5, D4, D5, E2.
Easy "Perfect" victories
Use your E-tank to get maximum health just before killing a Boss.
Fight against Akuma
Complete the game with 3 or more Perfects. After the final battle, Akuma will challenge you.
Fight against Sagat
Get at least four "Perfects" in Boss Rush mode before fighting Bison, and Sagat will challenge you before fighting Bison.
Guile's Theme
Pause the game in any level, then hold Jump (default L) and press U D D D (default keys W S S S) to have Guile's Theme replace the background music until you put the code in again.
Hadoken without defeating Ryu and Sei'ei Enbu
On de title screen,hold jump and shoot buttons for six seconds. There will be a chime to let you know that it worked. Hadouken: Once you have entered the code, Try a regular Hadouken like you would in Street Fighter with Ryu. You can also charge the Hadouken by holding the shoot button. This does not use the Weapon meter. Sei'ei Enbu: Press the Shoot and Swap 1 buttons at the same time. This will activate the Sei'ei Enbu, which uses the weapon meter. You cannot deactivate this once it is activated.
Play as Mega Man without his Helmet
To play as Mega Man without his Helmet, hold shoot on Ryu on the stage select screen and then press Right Right Right Left. If entered correctly, a sound will play and Mega Man will lose his helmet on the stage select screen.
Start with 4 E-tanks
At the title screen, select Password, then enter this: A5, B1, B3, C4, D2, D3, E1, E4, E5.