Original URL: http://www.psxextreme.com/ps2-cheat-print/403.html
Area 51

Cheat: Unlockables
Final Secret:
Get all the secrets to unlock the final secret, which is page 5.
Secret Tapes:
If you scan all five databank items in each stage, you get one secret. Beating the game yields one secret.
Alien Multi-player Avatar:
If you beat Campaign mode on the Hard difficulty setting, you'll get alien Gray as a selectable multi-player avatar.