Does a lot of things that add to the immersion that they'll be too afraid to ever do again for the sake of convenience. Faction quests that will ruin your standing with another faction, so you can't complete everything in a single playthrough (you'll still have plenty to do though, and it leaves more for future playthroughs). Fast travel costs gold and only exists in ways that make sense in-universe, you'll have to walk to anywhere else you want to go like a cave and NPCs will usually give detailed instructions on how to get there, recorded in your quest journal like it would be in a real journal, without quest markers. You can kill anyone, even NPCs essential to quests, and you may want to do so because of an item they have or because it's the way you're roleplaying your character. You can fly anywhere, and there isn't any spot you could get to that'll break the immersion like the walled cities in oblivon and skyrim being interior cells. Dungeons with optional paths and secrets, some requiring levitation, that aren't like skyrim's linear dungeons that always weirdly loop back around to the entrance. Most dialogue is read and not voiced, meaning they can have characters say a lot more and you can read at your own pace.