Energy Refill after boss rematch:
In Seth's Lab, find the computer in the background of the room where the eight Boss rematches occur. It has two large black and white swirling orbs. Shoot the orbs with a charged Mega Buster shot to get a large health tank and a large weapon energy tank. Those orbs will respawn after every Boss fight.
Hidden Abilities Codes:
Activate the following cheats by entering the corresponding codes at the title screen:
CHEAT FUNCTION - CHEAT CODE
Genin Jinn (Shadow Clone and Turbo MegaMan) - Press shoot and (Shift Weapon Right) button at the same time. Warning: cannot be disabled once used
Have the ability to use Hadoken manually without any meter or defeating Ryu. - Press and hold the jump and fire buttons for about 5-6 seconds.
Easy perfect hint:
Before you kill your stage boss, use your E-tank to refill your health back to maximum. This trick will make the game think you've earned a perfect in the round. Once you kill your boss when your health is full, you will earn a Perfect.
More E Tanks:
If you need more E tanks to complete the game, simply let the timer after you die hit 0. Then, go back into the game and you will have all the tanks you previously collected and recollect the E tanks from the levels all over again.
After pausing the game in any level, 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.
Play as Mega Man without a helmet:
Hold shoot on Ryu on the stage select screen and then press RIGHT (3), LEFT. If entered correctly, a sound will play and Mega Man will lose his helmet on the stage select screen.
Fight against Akuma:
Complete the game with 3 or more Perfects to have Akuma challenge you after the final battle.