Nightmare House is a very popular mod, as well as a two-part series of mods, with its sequel being Nightmare House 2. The mod has much recognition and is very popular in Let's Play videos on video hosting websites. The first Nightmare House has considerably less custom content than its sequel.
Finding the front door locked, the Patient heads to find another way in. He enters through the cellar.
After leaving the house, the Patient finds the yard crowded with zombies, which try to kill him. He ends up heading to his vehicle only to discover his path blocked, so he is unable to escape.