Duke Nukem 3D might be a light-hearted, over-the-top and comical parody of countless action and sci-fi movies, but don't let that fool you. It still plays enough sci-fi and horror tropes straight to be creepy and even frightening at times.
- There are naked women trapped in alien plant matter throughout the game, who mutter "Kill me" in a desperate tone when talked to; it's a bit creepy, but soon you get used to it. All you can do is either kill them or leave them to their fate. Even worse is the poor woman in the intro in Episode 4: The Birth. As if being impregnated and giving birth to the alien's new Queen isn't bad enough, there are Protector Drones surrounding her, watching with joy as she screams in agony and presents them with their abomination of a ruler. When you finally reach what's meant to be this room at the end of the episode, nothing but a gory mess remains splattered all over, implying the woman burst apart.
- Some women are also cocooned in underwater sections as well, which means that either 1. they are already dead or 2. the aliens still keep them alive through means unknown. And one particular sprite has the captive woman glare at you while spotting red eyes. What else could the aliens have done to them?
- Thankfully in the Nintendo 64 port, you're able to rescue captive babes anyway (hence the "babes rescued" in the level-end screen) but still...
- The Assault Commander. "Suck it down!" "Boom!", Duke gets reduced to Ludicrous Gibs. Not to mention their creepy heavy breathing, and the fact that they appear to be shooting those rockets out of their rectums.
- The Protector Drone. Horrific appearance and sound, loves to hide in dark areas where its glowing red eye is the only thing visible, moves like grease lightning and attacks with shrink rays.
- Here's a rather infamous Goddamned Bat: the Protozoid Slimer (pictured above). A Face Hugger Expy which after attacking blocks the screen, allowing you to see him munching on Duke's face. They're hilariously wimpy and barely deal damage unless you panic and fire the RPG by accident when one's on your face (and end up killing yourself), but that doesn't stop a good handful of players from jumping in their chairs or outright scarequitting the game upon sight of one that isn't even close or even hearing one hatching from an egg or simply announcing its presence. Add to this the fact that the first level (E2M2, "Incubator") and indeed most of the levels they appear in, lack much in the way of lighting.
- Oh, and in the core game the Mighty Boot doesn't work on the Slimers; that function was added in the Atomic Edition. Consider yourself lucky if you're playing on the EDuke32 source port with the third-person camera activated. Also, according to the manual, they attack Duke by sucking his brain out through his nose!
- And to rub more salt to the wound, the Slimers themselves in "Lame Duke" build were originally immune to all attacks (except the Tazer, which will latch them out). On the other hand, their design in "Lame Duke" is nowhere near as scary as in the final product.
- One last thing about the Protozoid Slimers. It is possible for them to engage a fellow enemy in combat - only to engulf them on the spot. The same thing applies to enemy corpses too - be thankful they are nowhere near as dangerous to Duke himself.
- In the Duke Nukem 3D-themed DLC for Pinball M, Protozoid Slimers are back, along with their eggs. Hitting them emits an awfully familiar sound of their activity, and one Slimer will even crawl up on the screen to kill you when you run out of balls.
- Not only you should fear the Protozoid Slimer, there's another one that's quite worse: The Sentry Drone. This abomination is a fast, intelligent, flying metal sled, bearing a creepy "smile" on its face that'll charge and suicide bomb RIGHT IN YOUR FACE! While they're not quite durable as they seem, their charging attack will cause Duke serious damage, especially on the harder difficulties. If one of those bastards charges towards you, you're in for a world of pain.
- Octabrains. While they look quite similar to the Cacodemon, they're hideous (complete with a built-in Slasher Smile), make creepy noises, are tough to kill, and seem to love sneaking up on you. Oh, and they're mostly found in dark underwater areas, along with Protozoid Slimer eggs and trapped women.
- Lunar Apocalypse is arguably the creepiest episode of the game, mainly because it's played a little more seriously than the others (well, except for the ending cinematic) and is generally lacking in parodies and gags. It's just you and a ton of aliens in abandoned, often dark facilities, in the middle of the inky blackness of space. Stand at one of the many windows, look out at the Earth, and just try not to feel a little isolated. Oh, and this also happens to be the episode where the Assault Commanders, Sentry Drones and Protozoid Slimers are introduced.
- Perhaps the creepiest part is the implied genocide of all the male astronauts on the moon base, as their gored corpses can be found sealed away in numerous locations or left to rot. It's actually unnerving just how violent some of these corpses are, as if they got utterly mauled and ripped apart before being placed in tubes to show off the brutality.
- The Abyss (the final level of the first episode), is pretty creepy as well. Several areas have unintelligible, vaguely Native American sounding chants, which make one wonder if the place is haunted. The second half of it also has everything bathed in a weird orangey light, making it seem more like you've entered Hell than some canyon in Southern California.
- At the end of the Abyss, as you enter the main room of the alien ship and approach the Portable Medkit sitting in the open, you hear a battlecry and witness a fanfare of explosions as the towering hulk of the Battlelord makes his entrance. If its minigun, mortar, high move speed and ability to literally crush you underfoot wasn't enough, its air-splitting roar (taken from The Land Unknown) is utterly terrifying.
