3. Night Vision Camera

I wish they had this filter on Instagram.

I hope you like everything on screen looking green and overexposed because you will be viewing most of the game this way. In the chaos the power to all but the main areas of the building has been cut, so the only way to navigate is with the night vision on the camera. This is also the only way to hide from enemies if you are spotted because we all know psychopaths cannot see the glowing screen on a camera.