All kinds of cheats
Mega Man 2 Cheat List

Villain Defeat Passwords
Flash Man: A2, C1, C2, C5, D3, E1, E2, E3
Wood Man: A2, C2, C4, C5, D3, D4, E1, E2, E3
Air Man: A2, C2, C4, C5, D4, E1, E2, E3, E4
Metal Man: A4, B1, B3, C4, D1, D2, E1, E3, E4
Bubble Man: A4, B1, B3, C4, D2, D4, E1, E3, E4
Crash Man: A4, B1, B3, C4, D2, D3, D4, E1, E3
Heat Man: A1, B2, C1, C4, C5, D1, D3, E3, E5
Quick Man: A2, B1, B3, B5, C2, D1, D2, D4, E4

All Weapons
For all weapons and items plus four energy tanks, enter the password "A5 B2 B4 C1 C3 C5 D4 D5 E2".

Long Jumps
If you pause in the middle of a jump, you'll reset Mega Man's downward velocity. If you press Start rapidly at the height of a jump, you can coast for long distances. This also makes Mega Man "phase out", causing most bullets to fly through you without harm.

Password for Dr. Wily's Castle
To skip to the fourth level of Dr. Wily's castle, enter the password "A1 B2 B4 C1 C5 D1 D3 E3 E5".

Mega Man 3 Cheat List
Passwords
All weapons, All Items, 9 ETs, no Doc Robots
Blue: A3 B5 D3 F4 Red: A6
All weapons, All Items, 9ETs, Dr. Wily Stage 1
Blue: A1 A3 B2 B5 D3 F4 Red: A6 E1
Spark Man defeated
Red: C5, F4
Snake Man defeated
Red: C5, F6
Needle Man defeated
Red: D3, E6 (Rush Jet Included)
Hard Man defeated
Red: C4, E6
Top Man defeated
Red: A3, C5
Gemini Man defeated
Red: B5, C5
Magnet Man defeated
Red: C5, F5
Shadow Man defeated
Red: C5, D6 (Rush Marine Included)

Slow Motion
To slow portions of the game to a crawl, hold Up on Controller Two while playing.

Invincibility
If you do the high jump trick press RIGHT on controller 2 while playing and jump into a pit, you do not die, and can walk around in it. Once in the pit, keep jumping in and out, and eventually your energy will drain but you will still be alive. You are now invincible. Jump out of the pit and your energy will stay down... you do not need to keep holding RIGHT on C2.

Note: If you pick up any energy items or use an Energy Tank, you will no longer be invincible...and you can still die if you fall on spikes. If you have trouble using it, try releasing RIGHT once you are in the pit for a second.

Mega Man 4 Cheat List
All Weapons and Items For all weapons and items, enter the password "A1 A4 B5 E2 F1 F3".

Mega Man 5 Cheat List
All Weapons and Items
Blue: B4 D6 F1 Red: C1 D4 F6
Level Passwords:

Charge Man Defeated Red: C1, D4, F6; Blue: B4, D6, F1
Crystal Man Defeated Red: A5, D2, E3; Blue: B1, B3, E5
Dr. Wily's Lair Red: C1, D4, F6; Blue: B4, D6, F1
Gravity Man Defeated Red: A5, B1, F4; Blue: C4, E5, F1
Gyro Man Defeated: Red: A5, B1, E3; Blue: B3, E5, F1
Napalm Man Defeated: Red: A5, C1, E3; Blue: B3, E2, E5
Star Man Defeated: Red: B1, B6, F4; Blue: C4, E6, F1
Stone Man Defeated: Red: C1, E3, F6; Blue: B3, D6, E2
Wave Man Defeated: Red: B1, B6, D3; Blue: B3, E6, F1

Mega Man 6 Cheat List
All Weapons and Items
For all weapons and items, enter the password "B6 D4 F2 F4 F6".

Mega Man 7 Cheat List
All Weapons and Items
To start the game with all weapons and items, enter the password "7 2 5 1 5 8 4 2 2 8 4 7 6 1 3 7".

Final Stage
To skip to the final stage of Dr. Wily's castle, enter the password: 1415 5585 7823 6251 and press Start.

Mega Man 8 Cheat List
Animation Test
To access the Animation Test and extra voices in the Voice Test mode, highlight "Bonus Mode" on the start screen, hold down L + R and press Start. The animation test will now be available allowing you to watch all the FMV segments in the game (including the ending). Also, the Voice Test will now have voices for all the Bosses, including Cutman and Woodman.