4. Library (Halo)
Like running for exercise, nobody actually enjoys fighting the Flood, the parasitic space zombies of the Halo series. You enjoy the creepy build-up ("ohshitohshitohfuckohgoddamnitshit"), the first few moments ("OHSHITOHSHIT") and the relief and pride you feel when you're done, but the actual bulk of it is an agonizing slog through too many ammo clips and interminable dark corridors.
Nowhere in the series is this worse than the Library level of Halo: Combat Evolved, in which you've set out to retrieve an ancient artifact from an abandoned installation. Standing in between you and your goal is only all of the Flood in the world. With the Flood coming at you from all sides, finding the right path through the endlessly repetitive gunmetal grey hallways becomes a Sisyphean ordeal, forcing you to fight wave upon wave of skittering baddie when all you want to be doing is driving Warthogs on the beach. Worse, what creepy or tense atmosphere that might have been achieved is ruined by 343 Guilty Spark hovering around, humming and mocking you adroitly. Halo is a lot of things, but survival horror? Not so much.
3. Xen (Half-Life)
For most of Half-Life, you beat zombie scientists to death with a crowbar, fight backflipping black-ops ninja assassins, and navigate a futuristic research facility that's being pulled down around your ears. Then, after beating back wave after wave of murderous marines and alien scum, you travel through a portal to the source of the alien invasion, at which point the game goes from "Check out all these cool, constantly changing environments!" to "Check out this vast, empty void!"
Gone are the awesome three-way dynamic battles between the factions struggling for control of Black Mesa. Gone are the NPCs whose goofy dialogue and horrific deaths were a constant source of brevity. Gone are the airducts to crawl through, industrial equipment to climb on, and all the vibrant, decaying locales that made Black Mesa such an immersive environment. Instead, you get the emptiness of space and some jumping puzzles, which, frankly, are a lot more annoying when you can't even see your feet. No puzzles, no interactions, no plot twists, just hopping. The tedium of Half-Life's overlong last segment is made up for by an intense final boss and a super-creepy, super-memorable ending, but only barely.
Full disclosure: I actually totally enjoyed Xen, but I also totally enjoyed the Nikki and Paolo episode of LOST, so maybe don't trust me.
2. Killer Croc's Lair (Batman: Arkham Asylum)
You may notice a trend emerging: For most of these levels, what makes them so terrible is that they ditch that game's best qualities. To advance, the player has to slog through stuff they never signed up for, like completing jumping puzzles, survival-horroring, and shooting and shooting and shooting. Worse, they severely tax the goodwill built up towards the game, so when a terrible level is also a final level, it can almost overshadow what was a masterpiece up until that point.
The "battle" with Killer Croc in Arkham Asylum exemplifies this perfectly. A huge part of what makes Arkham Asylum such a great game is the extent to which it makes you feel like Batman. You're swinging from gargoyles, setting traps for cowardly, superstitious criminals, and laying down rough justice left and right. In Killer Croc's sewers, though, you're collecting mold spores to make an antivenom, all while moving slowly enough that Croc can't sense where you are and attack you, making the whole level a leisurely fetch quest. Batman should be striking swiftly from the shadows, not sauntering, and certainly not strolling. By stripping the Batman out of Batman, the game kills its own momentum and wastes your time. Don't worry, though: When you finish, you still get to be Batman.
1. The Path of Hades (God of War)
Kratos, antihero of the God of War series, is so badass that even Hell itself can't hold him. It can, however, bore and frustrate him to no end. For most of the level, Hades is red, misty, repetitive, and sparsely populated. The cool, brain-stretching puzzles of the rest of the game are replaced by jumping on moving platforms and occasionally fighting guys who are on fire. This might be a forgivable bit of ill-advised tedium if it weren't for the tower of blades.
The fucking tower of blades.
Imagine climbing the rope in gym class. The gym is empty, it's just you, but in the back of your mind, you can hear all of the taunts your classmates would be throwing at you. Now imagine that the rope is twisting as you climb it. Now imagine there's someone yelling "STOP!" and "GO!" at you from the bottom of the rope, but you have almost no idea what or when they're going to shout next. Now imagine that if you hesitate for more than a second or two, you have to go all the way back to the bottom, receive a slap, and start climbing again. Now imagine that you have to get to the top twice. That's the fucking tower of blades.
Luckily, the rest of the game's pretty good for blowing off all that stress.