Nightmare House is a free two-part horror modification of Half-Life 2. It can be found here (Nightmare House 2 includes a revamped version of Nightmare House 1).Nightmare House 1 is a simple horror mod with no changes to the Source engine but some model edits. In it, you play a nameless protagonist who crashes his car in the middle of nowhere. Venturing into a nearby house, he finds it haunted by zombies and a mysterious ghostly woman. Eventually he escapes, but before he can get back to the road, the woman appears and blocks his path, and he blacks out.Nightmare House 2 features more changes to the game engine, and a far longer storyline. In it, after the events of Nightmare House 1, the protagonist wakes up in a cell at the mysterious "Never Lose Hope" hospital, a massive hospital in the middle of nowhere. Featuring an actual plot, you attempt to escape the now zombie-infested hospital with the aid of various characters, and try to find the explanation behind the mysterious ghostly woman who seems to be following you.Page needs more love.Warning: You must have Half-Life 2: Episode 2 installed in order to run it.
An Axe to Grind: The first weapon the player gets in either game is an axe.
Ambiguous Ending: The second game's "real" ending, in which you destroy the Core. Sure, you manage to destroy the Core, allowing Emily to finally get her revenge on Romero, but the game cuts off after her "Thank you." It's unclear what her idea of gratitude consists of, but it could be anything from a quick death over simply letting you leave the hospital to wanting to be your bestest friend. Forever. Further compounded by Fridge Horror when you realize that there's probably a reason that you're lying on the floor, being unable to move or do anything but look around after destroying the Core.
Ambiguously Evil: One could argue the point of whether or not Romero is really, truly evil. There's no proof that he did anything to Emily, and most of his actions were in self defense.
Badass Crew: The SWAT team mows down zombies like there's no tomorrow.
Batman Gambit: The first game resulted in the main character being hauled off to a hospital... which is the samehospital that Emily's husband resides at. It's all Emily's machinations.
Call Back: A few in the sequel, one of which includes mattresses being launched in the air.
Genre Shift: By the end of the second game, there's a lot more science fiction involved.
Haunted Technology: Dr. Romero says that the PA system in NH2 is completely automated. It's not, although it doesn't start being noticeable up til Chapter 3. It's both hilarious and creepy to hear the mechanical voice start showing signs of being a Deadpan Snarker.
PA: Thank you for participating in this fire drill. If it was a real fire, you'd be dead by now.
Murderous Mannequin: Subverted in Nightmare House 2, which has you spending one level with a lot of mannequins - which multiply and come closer when you do not look at them, but do not attack. You then encounter a SWAT officer knocking on a window from another room and uses gestures to show you where to go. When you get to the place where he was, there is just a mannequin...
No OSHA Compliance: Anyone with a slice of common sense would not put gas canisters next to a generator. Guess what you have in the power room.
Nothing Is Scarier: The more frightening scenes are often preluded in areas completely devoid of enemies, lighting, or both. They are far creepier than groaning zombies charging at you head-on.
Also, the mannequins mentioned above. They don't attack you, they don't even make any movements. And yet they managed to become one of the creepiest elements of the game by having a nasty habit of appearing right behind you to spook you as you turn, and replacing a friendly NPC who were gesturing you the way to go just moment ago.
Puzzle Boss: The Core. You have to break the fragile wood planks supporting it.
The aforementioned scene involving the SWAT gesturing for you to flip a switch and open the door is visually similar to Cryostasis where a man apparently trapped in an elevator shaft bangs on the glass of the control booth and points to the controls just below him.
The hallway full of shadow people is a reference to a similar sequence in Metro 2033.
Similarly, the mannequin sequence refers to the ones in Condemned.
Your Mind Makes It Real: Romero summons "creepy" zombies from your mind during the finale. Whether or not they're real the rest of the time is uncertain.
Romero's diary mentions how the cook was a zombie and he killed him with the axe, which means that some of the zombies are real - or he is just completely bonkers. It's more likely that most of the zombies are real, and that Romero is just cloning them from his own or the Player's experience.
Maybe the axeisn't real either, and is actually still just lying there in front of the house with all your weapons from the first game.
Zombie Apocalypse: Happened in the second game. The zombies in the first game are likely just hallucations induced by Emily.