Doors are objects that can be moved by either walking through them or by shooting at them. Doors will block enemy line of sight when closed but when opened they will not. Doors will stop bullets, however the force of the bullets can open doors. Hitting a standard enemy (such as a mobster) with a door will knock them over, allowing the player to execute them.
- Doors are sometimes placed together to create double doors, this involves placing one regular door (regular doors open clockwise) and one mirrored door (mirrored doors open anticlockwise) next to each other.
- Dispite blocking line of sight to most enemies, enemies behind cover can see the player through doors and will attempt to shoot them even if the doors will block the bullets, this can be exploited to make them waste all their ammunition.