Even the character generator is overwhelmingly complex by today's standards, allowing you to create unique characters with different advantages and disadvantages (weakness in holy places, rapid healing in the darkness, forbidden armour type, immunity to magic, affinity with certain weapons, phobias, etc.).

Your level-up speed is tied to these strengths and weakness, so you can make a juggernaut of destruction who'd level up very, very slowly, a sickly warrior allergic to sunlight and physical activity who'd level up twice as fast, or any other combination of different traits and curses – though some can play horribly.

Daggerfall did a lot of interesting things but if I had to pick the best, it would be the dungeons: it made you fear them. In most games a dungeon is a short hallway with some rooms; if you're lucky, there is a lower level with another hallway. Not in Daggerfall. You go into a dungeon, you don't know when or IF you're coming back. You don't know if your weapons will last, if you have enough supplies, if you're prepared to deal with whatever you'll find there. Emerging from a dungeon alive was an accomplishment and I can't think of another game that managed to pull that off. Certainly not Skyrim where on your way to a quest dungeon you run into 3-4 lesser dungeons and clear them out while you're in the area.

The dungeons' design is fantastic and skill-based – walls and air shafts to climb, open areas to levitate, pits to jump over, flooded areas to dive into, hidden areas and doors, multiple routes, switches, elevators, teleporters and so on.

Basically, Bethesda put together a very detailed character system and built a procedurally generated world around it, as opposed to putting together a pretty game and throwing in some skills for the player's amusement.