Turbo mode:
Enable shortcuts and enter the character selection screen. Hold Start and press an attack button to select a character. Continue to hold Start and select a handicap and level with an attack button. Release Start after the match begins. Note: For two player mode, hold Start on both controllers until the match begins.

Fight as Dr. Doom:
Complete and save the game under the default settings. Turn off the "Shortcuts" option. Enter the character selection screen. Press Down, then press Down again and hold the button. Quickly press A, B, C in that order, holding each button down as the next button is pressed. At this point, Down + A + B + C should be held on the controller. The words "Captain America" will be spoken, but Dr. Doom's face and name will appear.

Fight as Thanos:
Complete and save the game under the default settings. Turn off the "Shortcuts" option. Enter the character selection screen. Press Up, then press Up again and hold the button. Quickly press Z, Y, X in that order, holding each button down as the next button is pressed. At this point, Up + Z + Y + X should be held on the controller. The words "Spider Man" will be spoken, but Thanos' face and name will appear.

Fight as Anita (Japanese version):
Enable the "Fight as Dr. Doom" and "Fight as Thanos" codes. Turn off the "Shortcuts" option. Enter the character selection screen with the default controller settings. Press Up, Right, Down, Left, Up, Right, Down, Left, Up, then quickly press X, Y, Z in that order, holding each button down as the next button is pressed. Anita will appear as a selectable character.

Disable vs. mode power gems:
Press L + R on controllers one and two before the match begins. The phrase "No Gems" will appear to confirm correct code entry.

Random character select:
Hold Left or Right until the pointer begins moving quickly at the character selection screen. Press any button to select a random character.

Alternate costume:
Turn off the "Shortcuts" option. Hold Up (if your character is in the upper row) or Down (if your character is in the lower row) for approximately three seconds and press any button at the character selection screen.

Continue fighting:
Hold L + R after the last round of the match ends to continue hitting your opponent. Alternatively, press Start immediately after winning the match to continue hitting the defeated character.

Throw pumpkins:
Use a reality gem, then press L + R.

Other moves:

Key:
JP: Jab punch
SP: Strong Punch
FP: Fierce punch
SK: Short Kick
FK: Forward kick
RK: Roundhouse kick
F: Forward
B: Back
U: Up
D: Down

Note: If you already know how to perform the moves, then follow these terms:
(L): Light Version of an attack ( listed beside the move)
(M): Medium version of an attack
(F): Fierce version of an attack

Combo Notations:
,: Connecting combo hits
S.: Standing (Example a standing jab: S.JP)
J.: Jumping (Example: a jumping strong: S.SP)
SJ.: Super jumping (Example: in air combos, super jumping forward: SJ. FK)
C.: Crouching move (Example: crouching Roundhouse: C.RK)
^: Super jumping after the launcher

Spider Man
11 hits: J.JP, J.SP, J.FP, C.SK, C.FK, S.RK, ^ SJ.JP, SJ.SK, SJ.SP, SJ.FK, (L)Spider Swing
The first 3 hits of the combo are done by jumping into the opponent. Try to get all three first hits in the air followed by the last three crouching ones. Then, super jump and finish the rest of the combo.

Wolverine
14 hits: J.SK, J.SP, J.FK, S.JP, S.SK, C.SP, S.RK, ^ SJ.JP, SJ.SK, SJ.SP, SJ.SP, SJ.SP, SJ.FK, Drill Claw
All first three hits are done just like the start of Spider Man's 11 hit combo. The Drill Claw must be aimed diagonally upwards to connect. Note: This combo only works against Magneto, Juggernaut, and the Hulk.

Psy-Locke
17-22 hits: J.SK, J.SP, J.FK, S.JP, S.SK, C.FP, ^ SJ.JP, SJ.SK, SJ.SP, SJ.FK, Butter Fly super (QCB+3 kicks)
Just like the previous two combos, her first three hits must be done while jumping in. To get the maximum amount of hits, tap the buttons on the super that ends the combo. Note: This combo only works on Juggernaut, and Hulk.