Unlock Final Secret
Grab all the other secrets to unlock the final secret page 5. Well, d'uh.Unlocking Secret TapesScanning all five databank items in each stage yields one secret. Completing the game yields one secret.
Alien Multi-player Avatar
Beat Campaign mode on Hard difficulty setting to get alien Gray as a selectable multi-player avatar.<3>Upgrading The Alien GrenadeIn the stage Life or Death, there is a small key on a dead soldier in one of the lifts where Cole starts the stage. Grab it to open the small lockers in the stage. One of the small lockers in the first power conduit pit has a databank item that upgrades the alien grenade it now homes in on enemies.