Broken Base: Daggerfall is a mixed bag. It's glitchy like you wouldn't believe, but the good parts are really good, especially for its time. Even now, the sheer variety of what you can do has not been topped by any other game in the series.
Complete Monster: Besides Mannimarco (see The Elder Scrolls), Queen Akorithi of Sentinel, like her late husband King Cameron, was a warmonger. Their designated-heir son was chronically ill and fairly uninterested in invading neighboring countries for their land, the latter of which was the kind of thing his parents liked doing when they could get away with it. Not only did they produce some more children and partially disinherited him, his interest in scholarly pursuits hit King Cameron's Berserk Button, so he and Akorithi murdered him by tossing him into a dungeon full of zombies and mummies just after a bad bout of the flu. By the end of Daggerfall, Queen Akorithi has used the power of the Numidium to conquer Bergama as well as the whole of northern Hammerfell. She dies of a plague not long afterwards.
Demonic Spiders: Liches and Ancient Vampires. Unless you're resistant to their magical attacks, they can kill you instantly.
Fan Nickname: The sheer number of bugs in this game caused many players to refer to this game as "Buggerfall."
Game Breaker: If you're Fire Resistant enough, you can just walk to a lich and let him blow himself up.
Once you become strong enough, you can just camp out in the woods and wait for poor enemies to jump onto your sword. Or you can just make a big HALT train and kill it. Either way, you will have much better loot than you are supposed to.
Good Bad Bugs: There are a large number, but principle among them is The Void, the black area beyond the wall mesh in houses and dungeons. Walking/jumping/climbing against certain wall types at certain angles would allow you to pass through them, which usually resulted in you getting stuck or falling to the bottom floor, requiring a reload. However, with practice and luck, it was possible to use the Void to cut through the labyrinthine layouts (not to mention avoiding enemies) to quickly reach your quest objective, a practice usually referred to as Void Running/Walking/Surfing. Occasionally the Void would also swallow up enemies, which while helpful against Vampire Ancients at level 2 could render extermination missions unwinnable.
Of course the patch gave us Alt+F11, which took you back one step. It pulled you out of the Void, and with it you could also retreat out of the dungeon if you had forgotten to set the teleport anchor.
Much like Oblivion and beyond, stores have closing times. Unlike Oblivion and beyond, however, you do not get kicked out at closing time. This lets you take things without being considered stealing.
A lot of the sound could be this sometimes, constantly playing the sound effects over and over again, "HALT!" is just one example.
Using DOSBox to play will at times (usually near treasure piles) introduce some ear-splittingly awful audio glitches.
Nightmare Fuel: The dungeons, especially those containing undead can be really creepy and scary when crawling around in a dimly lit dungeon with scary music and howls. Even if you clear the dungeon of EVERY monster, you'll still hear the noises as ambiance. This was proven with the crypts which only have 2-5 monsters at a time, I killed all of them and could still hear rats (in the walls? A glitch maybe?)
Scrappy Mechanic: You cannot repair magical equipment in any way. Once their durability expires, you can never use them again. This includes Artifacts.
This mechanic was introduced by a patch in an attempt to 'balance' overpowered magical items, but proved unpopular enough that methods to repair the items was re-implemented in a later patch.
Werewolves may seem like the best thing ever (Overpowers speed and stamina and attack) but if you spend too long in a dungeon, or even fast travel to a dungeon at a great enough distance. Your stats will eventually plummet to zero making most monsters able to 1-hit KO you. Of course you could just fast travel to a nearby town, then return to the dungeon. Except that massively cuts into your time limit. The Ring of Hircine fixes this, however. There are essentially no drawbacks to lycanthropy if you have said ring.