Cheat mode:
Select the "Code Input" selection at the options screen. Enter one of the following codes, then select the "Special Features" option, then "Cheats" to toggle it on or off.

Effect
 Code
 
Invulnerability
 GMMSKIN 
 
Regenerator
 FLSHWND 
 
Full rage meter
 ANGMNGT 
 
Unlimited continues
 GRNCHTR 
 
Double Hulk's HP
 HLTHDSE 
 
Double all enemies HP
 BRNGITN 
 
Half all enemies HP
 MMMYHLP 
 
Wicked punch
 FSTOFRY 
 
Puzzle solved
 BRCESTN 
 
Reset high score
 NMBTHIH 
 
Unlock all levels
 TRUBLVR 
 


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Cheat mode (in-game):
Find a terminal during game play, then enter one of the following codes to activate the corresponding cheat function. 

Effect
 Code
 
Hulk Transformed movie art
 SANFRAN 
 
Hulk vs. Hulk Dogs movie art
 PITBULL 
 
Desert Battle movie art
 FIFTEEN 
 
Hulk Movie F/X in Hulk Unleashed
 NANOMED 
 
Play as Gray Hulk
 JANITOR 
 


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Cheat mode (file edit):
Use a text editor to create a file named "args.txt" in the game folder with "hulk.exe". Enter one of the following cheat parameters on separate lines to activate the corresponding cheat function.

Effect
 Parameter
 
Unlock all cheat, movie art, Hulk Unleashed options 
 -fesoak
 
Unlock all options, including challenge modes 
 -supersoak
 
Skip introduction sequence
 -soak 
 
Disable audio
 -nosound 
 
Display frame rate
 -framerateicon 
 
Unknown
 -lighthack 
 
Unknown
 -window
 
Unknown
 -drawcode
 
Unknown
 -nocd
 

Other (useless) parameters to try:

-lighthack
-window
-framerateicon
-drawcode
-nosound
-nocd