Secret tapes
Scanning all five databank items in each stage yields one secret. Completing the game yields one secret.
Secret Rooms
Level 2: Shoot all the highest windows in the far wall in the hangar. When you are in the truck, shoot all yellow barrels, and you will discover another secret room.
Level 4: When you are driving on the STAAR jeep, shoot every yellow box.
Level 5: Shoot the sign which shows the words General Weatherby on the second door right away when this door opens.
Level 7: Shoot all yellow barrels in the first area where the four purple zombies are throwing barrels.
All brands, logos, and product names are trademarks or registered trademarks of their respective holders.