Thunder Strike: Operation Phoenix Cheat Codes for Playstation 2

Unlock Maniac Difficulty & Extra Helicopters
Finish the game on Hard Difficulty setting for Maniac Difficulty. Finish again on the Maniac Difficulty for a new helicopter.

Level Select
Go to the options screen and set Vibration to 1, Sound Effects to 0, Music to 0. Now hold L2 + L1 + R2 + R1 + CIRCLE + SQUARE. If you did it correctly, you should see blinking letters saying "SPOOKY CAT".