Justice League Heroes Codes -

Cheat mode
Press to pause game play. Then, hold + and press , , , to enable cheat mode. This will allow the other codes to be activated, as well as unlock all costumes.

Invincibility
Press to pause game play. Then, hold + and press , , , , , , , .

Unlimited Superpower
Press to pause game play. Then, hold + and press (x2), (x2), (x2), (x2).

Maximum abilities
Press to pause game play. Then, hold + and press , , , .

35 random boosts
Press to pause game play. Then, hold + and press , , , .

20 shields
Press to pause game play. Then, hold + and press (x2), (x2).

Bonus heroes
The following characters can be unlocked by spending the indicated amount of Justice League of America shields that can be collected during game play.

Aquaman: 27 shields 
Green Arrow: 76 shields 
Green Lantern (Hal Jordan): 84 shields 
Green Lantern (Kyle Rayner): 55 shields 
Hawkgirl: 70 shields 
Huntress: 53 shields 

Alternate costumes
The following characters can be unlocked by spending the indicated amount of Justice League of America shields that can be collected during game play.

Batman (classic blue): 59 shields 
Batman (Batman Beyond infiltration suit): 74 shields 
Flash (Jay Garrick): 21 shields 
Flash (Walter West): 48 shields 
Green Lantern (retro): 23 shields 
Green Lantern (bold): 30 shields 
Martian Manhunter (modern): 29 shields 
Martian Manhunter (true): 15 shields 
Superman (black recovery suit): 32 shields 
Superman (Earth 2): 65 shields 
Superman (Kandor): 91 shields 
Wonder Woman (biker): 61 shields 
Wonder Woman (toga): 44 shields 
Zatanna (classic blue): 25 shields 
Zatanna (Identity Crisis): 38 shields 

Completion bonuses
Successfully complete the game to unlock the "Continued Play" option (to allow a new game to be started with all previous stats and items unlocked" and an alternate main menu background (with characters from the game).

Successfully complete the game under the Medium difficulty setting to unlock the Challenge missions, where you can choose any character.