X-Men: Reign Of Apocalypse

Hint: Special move:
Press A + B to do a special move. Note: This takes away a little bit of life.
Information in this section was contributed by AstroBlast62.

Press Attack + Down/Left. Note: This results in a different move for each character.
Information in this section was contributed by Rick Lackey.

Hint: Defeating Night Crawler:
Knock Night Crawler onto the spikes that appear from the floor. Keep punching him, and the spikes will help kill him quickly, often without hitting you back.

Hint: Cyclops:
Choose Cyclops when selecting a character. He has no punch combo, so you can continuously punch one enemy till he is KOd without having to stop, unlike the other X-men who can only punch three or four times. Note: This will not work on most Bosses. mini-Bosses and Sentinels.
Information in this section was contributed by ryan harris.

An easy way to complete the game is to use your points to increase your strength. Choose Cyclops, and as you complete levels, use your points on his strength. The game will be easier, and eventually your normal attacks will become stronger than your special attacks.
Information in this section was contributed by Daniel Baldwin.

Hint: Play as Bosses:
Complete the single-player mode. When you hook up the Game Boy Advances and select a mode, you can choose from Bosses (but not mini-Bosses).
Information in this section was contributed by William Bether.

Hint: Defeating all Bosses:
In this game, Bosses are easy to defeat. To do so, first, pin them against a wall with a rapid punch attack. When they stand up, move to a different level. They will try to get alongside of you, close to the wall. When they do, give them a punch series again. Repeat until they have been defeated.
Information in this section was contributed by James Kruk.