Mission 5, The Quarantine. As the first serious confrontation with a xenomorph that will relentlessly stalk you everywhere, the insidious layout means that many players met an impressive spike in difficulty the first time they played it. The level is divided in two areas: the first one has very few hideouts, most of them have an exposed side, there are wide pathways where the alien can easily see you, you are forced to move and turn around corners and spend time digiting a passcode; the second areas on the contrary has a lot of good spots for hiding, but it's really narrow and claustrophobic, and you can't easily see where the alien is going or how much it's close, chances are that if you slow down you will trap yourself because you hide in a point where it's difficult to get out without crossing the alien. There are however one Easy Level Trick and a shortcut for more advanced players.
Mission 9, not for its difficulty but because it's an interactive flashback without action or enemies, it's long, you can't skip it during a full run and it becomes boring after you replay it for the umpteenth time.
Mission 15 is probably one of the most, if not the most nerve-racking moment in the game. Although the xenomorph is gone, you have to make your way to the reactor core of the Sevastopol Station to find out what's wrong with it, on various paths that are crawling with either Working Joes, hostile humans, or both. At one point, you have to leave your firearms behind, practically leaving you defenseless, and most if not all the Working Joes you'll encounter then wear hazmat suits, making them immune to EMP grenades and the stun baton. You eventually get your weapons back, plus a new one that can dispatch even the hazmat Joes in one shot, but then you get to the base of the reactor. The base is crawling with hazmat Joes and, depending on the difficulty, you'll might not have enough resources to dispatch each of them. Things go From Bad to Worse when you finally actually get to the reactor core itself, in which it turns out there's a whole hive of xenomorphs down there.
The infamous Water Part, mostly because it's the first area of the game where something is relentlessly pursuing you and where you could most likely die your first time. Other than that, it involves platforming on boxes to prevent the monster from chasing you, using a lever that will open a gate for a limited time that you have to rush through. And a mad dash through multiple flooded hallways, shutting doors behind you to stall the monster for a few seconds.
Also the prison has annoyed some people due to it being full of intersecting dark hallways where a Servant can ambush you. Also there are multiple Servants in this area.
For first time players who made it past the first two Suitors, Amnesia: Justine has the Dungeon, and it will mostly likely be the place in which they die. Remember how easy it was to sneak around before due to the Suitors being blind? Guess what? The area is completely water-logged, so good luck trying to be quiet! The game forces you to move quickly as well due to the timing required, and there's literally no room for error, especially if the player wants to save the hostage. What makes it even worse is that the game's official ending is literally minutes away at that stage and that dying will mean starting over since there's no saving the game.
ObsCure: The Aftermath sort of does this with Mei's sister, Jun. It's almost painful enough to just let her die before she goes into it.
Outlast II has the notorious school segments. In a game that's already difficult thanks to its Trial-and-Error Gameplay, the school segments are the absolute worst since they're very directionless in spite of the more linear setting. Your objective is literally just finding a way out of the school, with no clues as to how. Plus, it's easy to go through a lot of batteries since the school is largely in complete darkness. Things go From Bad to Worse in later segments when the Stalker starts making appearances, who can only be evaded by literally just running away from it. The only saving grace is that his appearances are not randomized with each playthrough.
The Thing (2002) has a stage almost identical to Metal Gear Solid's staircase sequence, except you're going down, there are automatic turrets on every level (that can take up to five grenade hits to destroy), scalding steam vents, seemingly endless streams of scuttling creatures that pop out of dead bodies (and attack you from front and behind), and the medic, your only hope of surviving the stage, turns into a monster at random points. If you don't have enough health packs on you, or enough firepower, it's impossible to get through the stage. And at the end of this stage there's a bomb that kills all of your squadmates, and destroys their gear. If you don't have a flamethrower at the end of the level, you will NOT be able to complete the game.
Penumbra has Chemical Storage in Overture. It's not just because you'll be chased by a worm through doors you'll have to shut behind you, through barriers that will make you stop and take time to break them down, and over pools of deadly acid that require jumping and box pushing to avoid injury. It's that there's Schmuck Bait in the form of a metal barrier that tempts you into thinking it can hide you from the worm. Worse, at the end of the area you might think it's possible to have enough time to turn the valve and open the steel door, but in reality you're supposed to cause a cave-in.
Dead Space: Chapters 3 and 4 both have stages where you will wish you could just be throwing down with a swarm of Leapers. In 3, there's the gravity centrifuge, which when engaged means you need to run through it - and if you're out of a niche when the blade comes along you're reduced to a red smear on the ground. In 4, at one point, there's an objective where you need to run from cover to cover in hard vacuum and zero-gravity to avoid an inconvenient meteor shower. The hint you get for this is vague and unhelpful - it talks about "the walls" but it's not actually the walls that save you - and being caught out in the open means you get a warning about meteor impacts about, ooh, one second before you get torn apart by one.
For a game that is already Nintendo Hard if you have no idea what you're doing, part IV of Lakeview Cabin Collection is by far the most difficult of the levels. First off, the rooms in the house are randomized (but not crazily so). Secondly, while the enemies are weaker than most of the other levels, they make up for it by having alarm switches and traps. And last, any room with a vent has a likely chance for a giant rat to pop out, which move quickly and severely damage any survivor just shy of being a One-Hit Kill.
Corpse Party: The one where you, as Yuka, have to run from Kizami.
The insanely frustrating driving level down 59th Street in , because the steering is lousy. Though some believe the look and sound of that level make up for it.
The driving section with the bats, coming soon afterwards, where they drag your car up (possibly to your doom) and/or stop sticking to it completely at random; the black goo, which might or might not react to your flashlight, eating you up; and that final driving section, timed, where it's plenty possible to miss the right turn at the end.
Fixed in the PS3 Inferno port. While the 59th Street driving section is still unlikely to be beat at first try, the improved controls, Sarah's giving you directions as well as there being checkpoints along the way actually render the whole sequence somewhat fun if still challenging.
Five Nights At Freddys VR Help Wanted has the Plushbaby level, where you're tucked in the Prize Corner and have to fend off the eponymous murderous plushie with your flashlight. The problem? Oh, there's a number of them.
There are multiple Plushbabies going after you, sometimes at the same time.
There are over a dozen places they can spawn, and the only indicator that a new one had appeared is a sound that doesn't necessarily come from their direction.
The Prize Corner is filled with toys they're hiding behind.
The flashlight - the only source of light in the level - has limited battery life. Let it run out in full, and you have to wait precious seconds for it to recharge before you can use it again.
And that's not to mention the Hard Mode version of the level, where all the toys in the Prize Corner are Plushbabies, and you have to look for the ones with no iris in their eyes, as they're the only ones going after you.
Chapter 9, though regarded as the best level in the game, is notorious for the fact that that's the chapter where Ruvik actively hunts the player down. Though Ruvik is slow, any contact with him is instant death and his AI is smart enough to teleport instantly towards you depending on the occasion. The worst part? His encounters are completely randomized; there's absolutely no indication when or where he'll appear outside the screen turning blue and the background music changing.
The following chapter, Chapter 10, has you slog through a dark maze-like setting that feels like a combination of all the worst parts of the game. Death traps are everywhere, enemies can get the jump on you when you least expect it, you'll have a few encounters with the Traumas (including a pair of them simultaneously), and eventually fight not one but two bosses that both extremely difficult due to their fast attacks and instant kills.
And the chapter following that, though not as long, is absolutely annoying since there are enemies just about everywhere you go. Many of them are armed with melee weapons, crossbows, molotovs, dynamite, guns and some of them wear bulletproof armor. Then you'll have to face enemies where you can't necessarily fight back, such as dealing with a fish-like monster who will kill you the second it comes in contact with you.
"Into the Abyss" features Slenderman and Kate chasing Lauren simultaneously, nineteen possible spots for only six generators, and a maze-like layout. It gets worse in Hardcore Mode, where Lauren also has to collect gas canisters before activating the generators.
"The Arrival" features Slenderman chasing Lauren through a burning forest. Both Slenderman's Combat Tentacles and the raging wildfire will instantly kill Lauren on contact. In Hardcore Mode, the tentacles move faster and the wildfire burns faster, making the bunker at the end of the level even harder to reach.
