X-Men: The Official Game [NDS]

Completion bonuses:
Complete Story mode to unlock Boss Rush mode and Survival mode.

Score Attack mode:
To unlock Score Attack mode, beat level 1 in Story mode.

Unlockable Costumes:
In all the missions, except the tutorials, unlock various costumes for Wolverine, Nightcrawler, and Iceman by finding every Sentinel Tech and Weapon X

Folders:
COSTUME - HOW TO UNLOCK
Iceman's Casual Clothes - Collect all Weapon X Folders as Iceman.
Iceman's Comic Clothes - Collect all Sentinel Tech as Iceman.
Nightcrawler's Casual Clothes - Collect all Weapon X Folders as Nightcrawler.
Nightcrawler's Comic Clothes - Collect all Sentinel Tech as Nightcrawler.
Wolverine's Casual Clothes - Collect all Weapon X Folders as Wolverine.
Wolverine's Comic Clothes - Collect all Sentinel Tech as Wolverine.

Finding Tech pieces:
To save time, run through the level on novice to find all six Tech Pieces. Then, distribute mutation and save the game. Go back on the higher levels to obtain the missing mutations without worrying about trying to find the pieces (especially on timed missions).