Complete the following tasks to unlock the corresponding playable characters.
Black Panther:
Collect the 5 Black Panther Action Figures. There is one in each act.
Blade:
Play Crane Game in Murder World
Daredevil:
Collect the 5 Daredevil Action Figures. There is one in each act.
Dr. Strange:
Rescue him from Mandrin in Act 1.
Ghostrider:
Rescue him from Mephisto in Act 2.
Nick Fury:
Complete the game on Easy or Normal mode.
Silver Surfer:
Complete ALL the Comic Book missions.
Unlock Fourth Alternate Costume
Either complete the Combat Training challenge or alternately, get a 'Bronze' rank in a character's Comic mission to unlock their fourth costume.
Unlock Hard Mode
Complete the game on the Normal difficulty setting to unlock Hard mode.
Unlock Second and Third Alternate Costumes
Either gain between two and four levels with a character or alternately, defeat 30 enemies with a character to unlock their second costume and defeat 175 enemies with a character to unlock their third costume.