Thunderstrike: Operation Phoenix Cheats
By going to the options screen. Change VIBRATION to 1 and SOUND EFFECTS and MUSIC to 0. Then, enter code
Code: press and hold L1 + L2 + R1 + R2 + Circle + Square.
Finish the game under the hard difficulty. The maniac difficulty and a bonus helicopter and will now be unlocked. The bonus helicopter flies, turns, climbs, descends, and shoots faster. After finishing the game under the maniac difficulty you will unlock a third bonus helicopter, which you can use on any difficulty. It has the same top speed...