Call of Duty: World at War

You'll need 8,250 points to unlock all doors. There are 9 of them scattered around and shouldn't be too hard to find.

Door Locations

1. Open the door to the right of mainframe. It costs 750 points to open.
2. After opening 1st door, go straight and turn left to find door #2 for 750 points.
3. Once here you will see a staircase, to remove debris you'll need 1000 points.
4. After clearing the debris, turn right and you'll see a door there for 750 points with Teleporter #1 inside.
5. If you head back you'll pass the Double-tap Root Beer, go across the bridge and you'll see some debris. It costs 1000 points. If you don't already know, to the right of this you'll see a Juggernaut Perk and some Bouncing Betties.
6. In here if you go straight, there are two doors. Go to the one near trench gun (right one) and you'll see this door costs 1,250 points.
7. If you went to the right one, go left this time. This door costs 750 points.
8. If you opened door #7, door #8 will be staring at you in the face as you turn around. This door is the one left of the Mainframe and it costs 750 points to open.
9. Door #9 is all the way in the end of map, past the original location of the "Mystery Box". Past this door awaits Quick Revive, the 3rd teleporter and the bowie knife.

Go for this trophy at the same time as Der Electrician, 40 Knives and Frequent Flyer (only do this one if you have the cash necessary and a teleporter linked up).