Hexen/YMMV

Demonic Spiders: The Wendigos are broken. They may die easily, but they shoot tons of ice balls that take out half your life if they hit you. And god forbid you play the highest difficulty (they shoot twice as fast). At least they only appear in a few levels.
- The Fighter likely has the biggest problem handling them, due to lacking any good ranged weapons on the first hub (which is where you encounter 90% of them). While you'd expect the Mage's second weapon to be ineffective against them, luckily it still harms them just fine.
- Hexen II gives you the skull wizards and shadow wizards who like to teleport behind your back, blast you and then teleport away when you return fire, only to repeat the whole thing again.
Goddamned Bats: Centaurs/Slaughtaurs. They're everywhere and they have shields which make them invincible for a short time after every hit. They really aren't that dangerous, but certain classes' weapons (read: Cleric) make them take forever to kill.
- Fortunately, the Cleric has the Wraithverge in his arsenal and that's a kill that a shield can't block. Granted, it sucks up a lot of mana, but if you can get the centaurs to cluster, one shot will take out a good chunk of their numbers.
- Ways before that, Cleric can dispatch the Centaurs pretty easily with poisonous flechettes.
- Not only this, Mage's lightning spell helps same way. A LOT.
- Hexen II has the flying imps who are frail, but nearly impossible to hit from afar.
Porting Disaster: The PlayStation version. Naturally, you get the port of the same quality as Doom for the Super Nintendo, but with floor/ceiling textures present and made for a console where such quality won't work anymore. Obvious screws include: one-sided enemy/character sprites, choppy framerate along with low resolution, several interior replacements and programming oversights, and, for a dessert, the soundtrack has been butchered in order to fit all those CD-DA tracks into the remaining part of the disc when they could've easily used XA tracks. To make the port even more frustrating, one save eats the entire memory card, compared to Total Meltdown which used, in the worst cases, seven blocks of it! Although, in its defense, it has pretty good FMVs for a game like this and more comfortable controls than the N64 version did. The loading times (from the CD, that means) are not large either.
- And, on a side note, that was developed by Probe. Yeah, the same guys who brought the first two Mortal Kombat games onto consoles.
That One Boss: None of the four Horsemen of the Apocalypse in Hexen II are pushovers, but the last one (War) is downright broken. The only thing he does is ride around spamming homing axes. The level you fight him in doesn't really have any places to take shelter and the axes (which do a crapload of damage) seem smart enough to fly around the few corners you can hide behind. Best thing to do is swallow your pride, use an invincibility item and unload all your firepower into the guy at point blank range.
That One Level: One particularly nasty section is a hidden room in the Guardian of Steel level that must be crossed in order to open the way to the secret level. You get teleported into a small room surrounded by several Wendigos (see Demonic Spiders) who must be killed before the walls of the room open to let you out. (or let more Wendigos in) At this point you don't have a great deal of firepower yet, so expect to take a beating.
- A good way to deal with the wendigos there is to grab the Wings of Wrath first (near the end of the hub). When teleported in the level, after killing wendigos that trigger the walls to lower, the player can fly as fast as he can for the elevators. The wendigos can then be attacked relatively safely from the main room of the map, through a window, using either flechettes (fighter) or the ranged weapons (cleric or mage). Confirmed to work even on the hardest difficulty.