Zombie Survival Modification. To simply put, the player and the human faction will be placed in a close quarter city map to fight off the zombie horde.
A very rough interior of a building without modifying the actual house model.
The explosive crates's mesh will be replaced with a door that doesn't do any damage upon destruction. The door will also have considerably more health, forcing the player to invest his/her ammunition in search of potential loot/safehouse.
Reminds me of Gary's Mod houses.