Unlock Dark Phoenix
To unlock Dark Phoenix beat Story Mode 2nd ending to get to the second ending let Bastion beat Magneto, when Bastion Beat Magneto he will face Phoenix, beat Bastion with Phoenix and then you will get the Dark Phoenix.
Unlock Bishop
To unlock Bishop beat Arcade Mode With Gambit.
Unlock Psylocke
To unlock Psylocke beat Arcade Mode with Besty.
Unlock Blob
To unlock the Blob beat Arcade Mode with Bishop.
Unlock Sentinel A
To unlock Sentinal A beat Arcade Mode With Cyclops.
AI Toggle
Go to the main menu and press UP, UP, DOWN, DOWN, A, A, B, B, X, X, Y, Y to turn off the AI.
Alternate Ways of Unlocking Costumes
Win 1,976 rounds to unlock the fourth skin. Play for 20 hours to unlock the eight skin.
Third Costume
Successfully complete the game in story mode to unlock that character's third costume.
Fourth Costume
Win twenty matches in survival mode with all characters.
Fifth Costume
Successfully complete the game in arcade mode under the hard difficulty setting with all characters.
Sixth Costume
Defeat all ten fighters in time attack mode in under fifteen minutes to unlock the sixth costume for the fighter you selected.
Seventh Costume
Select team mode and choose to fight with eight characters. Defeat all of the your opponent's team by using two or less of your own fighters to unlock the seventh costume for the character(s) you used.
Wolverine gets his original yellow/blue/black costume.
Phoenix gets a red/gold costume similar to Dark Phoenix.
Juggernaut, Gambit, and Psylocke get a costume similar to their comic book original.
Beast gets a blue costume with a yellow X on his chest, and he also has a helmet.
When you chose the seventh costume for Cyclops, Wolverine, Betsy, Juggernaut, Sentinel A (Sentinel), Gambit, Storm, Sabretooth, Rogue and Magneto, they will most commonly appear in their costumes if they were in a 'Vs.' series game (Marvel vs. Capcom: Clash Of The Superheroes, X-Men vs. Street Fighter, X-Men Children Of The Atom, Marvel Super Heroes vs. Street Fighter).
Eighth Costume
Win forty matches in survival mode as any character.
Classic Costumes
Some Characters Have Classic Outfits That Resemble The Classic X-men Characters:
Wolverine: Costume VII
Betsy: Costume VII
Forge: Costume VI
Gambit: Costume V
Juggernaut: Costume VII
Magneto: Costume VII
Nightcrawler: Costume VII
Sabretooth: Costume III
Rogue: Costume VI
Alternate Opponent Costumes
Play in survival mode as Gambit with his seventh costume. Continue until you have won twenty matches. After then, your enemies should be wearing all white costumes, or are partially invisible with markings that look like B, A, X, and Y buttons on them.
Toggle infinite supers
At the main menu, press Up(2), Down(2), A, X, A, X.
One-hit kills
At the main menu, press Up(2), Down(2), X, Y(2), X. Repeat the code for slow deaths.
Play as Bastion
Successfully complete story mode with Magneto without losing any matches to face Bastion. Defeat Bastion to unlock him as a selectable character.
Play as Sentinel B
Win twenty matches in survival mode to unlock Sentinel B as a selectable character.
Nightcrawler: Play in the Dimensional Rage
When in training mode as Nightcrawler, turn on "Infinite Specials" then perform the Dimensional Rage technique. You will be in the Dimension for the technique. Perform a different special other than Dimensional Rage and make it contact. This will cancel Dimensional Rage and leave you in the darkness. To exit, perform the Dimensional Rage again and let it finish properly.
Apocalypse appearance
In the Crypt level, fight in the lowest area for a chance to see Apocalypse. His sarcophagus rises out of his tomb and separates, leaving him floating in the air. He laughs, then goes back inside. This is sometimes triggered by good fighting.