Hulk, The Cheats

If you get something to throw, pick it up then jump on the roof. Jump while on the roof. If done correctly, you can blow up the helicopters.

Invulnerability:
Select the "Code Input" selection at the options screen, then enter GMMSKIN as a code to unlock this option at the cheats menu. The Hulk and Bruce Banner will be invincible.
Information in this section was contributed by jessedeez.

Regenerator:
Select the "Code Input" selection at the options screen, then enter FLSHWND as a code to unlock this option at the cheats menu. The Hulk will regenerate faster.
Information in this section was contributed by jessedeez.

Full Rage Meter:
Select the "Code Input" selection at the options screen, then enter ANGMNGT as a code to unlock this option at the cheats menu. The Rage meter always remains full.
Information in this section was contributed by jessedeez.

Unlimited Continues:
Select the "Code Input" selection at the options screen, then enter GRNCHTR as a code to unlock this option at the cheats menu.
Information in this section was contributed by jessedeez.

Double Hulk's HP:
Select the "Code Input" selection at the options screen, then enter HLTHDSE as a code to unlock this option at the cheats menu.
Information in this section was contributed by jessedeez.

Double All Enemies HP:
Select the "Code Input" selection at the options screen, then enter BRNGITN as a code to unlock this option at the cheats menu.
Information in this section was contributed by jessedeez.

Half All Enemies HP:
Select the "Code Input" selection at the options screen, then enter MMMYHLP as a code to unlock this option at the cheats menu.
Information in this section was contributed by jessedeez.

Wicked Punch:
Select the "Code Input" selection at the options screen, then enter FSTOFRY as a code to unlock this option at the cheats menu. The Hulk will have one hit kills.
Information in this section was contributed by jessedeez.

Puzzle Solved:
Select the "Code Input" selection at the options screen, then enter BRCESTN as a code to unlock this option at the cheats menu. Puzzles will immediately be solved.
Information in this section was contributed by jessedeez.

Reset High Score:
Select the "Code Input" selection at the options screen, then enter NMBTHIH as a code to unlock this option at the cheats menu.
Information in this section was contributed by jessedeez.

Unlock All Levels:
Select the "Code Input" selection at the options screen, then enter TRUBLVR as a code to unlock this option at the cheats menu.
Information in this section was contributed by... 

Enter ANGMNGT on the Code Input menu to unlock this cheat. This causes the rage meter to constantly remain full.

To kill Half-Life faster, knock him into the generators.