Start new game with 4 E-Tanks
Go into password menu, then enter this code. You will start a new game with 4 E-tanks.
A5, B1, B3, C4, D2, D3, E1, E4, E5 - Start with 4 E-tanks
All Eight Bosses, 4 E-Tanks
At the title screen, select Password, then enter this:
A5, B2, B4, C1, C3, C5, D4, D5, E2 - All Eight Bosses, 4 E-Tanks
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.
Hidden Abilities Code
At the title screen. Press and hold the jump and fire buttons for about 5-6 seconds. You'll have the ability to use Hadoken manually without any meter or defeating Ryu.
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.
Alien - Complete Alien Ship on Normal difficulty
Barbarian - Complete King's Arena
Bear - Complete the game with Skeleton
Beekeeper - Complete the game with Barbarian
Brute - Complete the game with Iceskimo
Civilian - Complete the game with Peasant
Conehead - Complete Volcano Arena
Cultist - Complete Ice Castle on Insane difficulty
Fencer - Complete the game with Industrialist
Fire Demon - Complete the game with Orange Knight
Gray Knight - Complete Barbarian Boss on Normal difficulty
Iceskimo - Complete Icy Arena
Industrialist - Complete the game with Blue Knight
King - Complete Pipistrello's Cave on Insane difficulty
Necromancer - Complete Industrial Castle on Insane difficulty
Ninja - Complete the game with Fire Demon
Open-Faced Gray Knight - Complete Catfish on Insane difficulty
Peasant - Complete Peasant's Arena
Royal Guard - Complete the game with Green Knight
Saracen - Complete the game with Royal Guard
Skeleton - Complete the game with Red Knight
Snakey - Complete the game with Thief
Stove Face - Complete the game with Gray Knight
Thief - Complete Thieves' Arena
More E Tanks
If you need more E tanks to beat the game. Just let the timer after you die hit 0, go back into the game and you will have all the tanks you previously collected and you can recollect the E tanks from the levels all over again. I got 10 E tanks at one point.
How to get an easy perfect
Just before killing your stage boss, use your E-tank to refill your health back to maximum. Doing this will trick the game into thinking you've earned a perfect in the round. Once you kill your boss when your health is full, you will earn a Perfect.
Fight Against Sagat
To fight Sagat, you must obtain 4 perfects in the boss rush before Bison. Sagat will show up before the fight with Bison.
Energy Refills after Boss Rematches
In the room in Seth's Lab where the 8 boss rematches are, there's a computer in the background with two large black and white swirling orbs. Simply shoot these with a charged mega buster shot and you will get a large health tank and a large weapon energy tank. After each boss fight, these same orbs re-spawn, essentially giving you a large health and weapon tank after each boss fight.