This game is also available on Xbox.
**Trench Tool**
In the "Search For Yamashitas Gold" level look out for a lotus flower on a statue in the palace. When youve found it (it can be tricky to find) grab the flower and you will a hole. Head down the hall and go into the room which has a gold statue in it.Press X on the pedestal and a message saying "You have reached enlightenment" will appear.Now go through door on the right and you'll find the trench tool.Use it for the extra unlockables.
**Extra Unlockables**
Infinite Ammo - On the level "Day Of Infamy", when you see a soldier being sprayed with steam (well some sort of gas!), go up to him and press X to use your trench tool.You now have unlimited ammo in the bonus menu.
Bullet Shield - In "Fight For The Philippines" look for the pile of dirt in a corner of the baseball field.Press X to use your trench tool.You now have bullet shield in bonus menu.
Silver Bullet - In "Midnight Raid On Guadalcanal" search for a pile of dirt by a building with no walls and press X to unlock silver bullet in bonus menu.
Achilles Head - On the level "Yamashitas Gold" go to the room with a small staircase. At the bottom of the stairs is a very small air vent, again, press X to unlock.
Invincibility - During the level " Super Carrier Sabotage", go into the room with all the lockers.Look for the locker thats darker than the rest and use your trench tool to get invincibility in the bonus menu.