Fun for the first few days.
The gameplay is also flawed. The issue everyone complains about is the leveling system, which makes no sense to me. The whole point of an RPG is to level your character and become stronger. In unmodded Oblivion, you never become stronger. In fact, if you level too fast, you will become weaker due to the more powerful creatures that appear.
The number one gripe I have about this game is the quests. It is ridiculous how uninventive the quests are. There are four guilds, a main quest, and an Arena. The Fighter's and Mage's guilds are a joke, they are just a bunch of random dungeons strung together and labeled as a guild. The Mage's Guild has a semi-plot, which leads up to an anti-climactic easy fight. I'm not even sure what the plot of the Fighter's Guild is, as all you seem to do is go to a couple of caves and kill monsters. The Thieves Guild, Main Quest, and Arena are all decent, but not great, and are very easy to beat.
Where this game truly shines is the Dark Brotherhood. It is, IMO, one of the most fun guilds in any RPG. The quests are so creative, and it is one of the few times when the A.I actually works. I won't provide any spoilers, but the plot is great, and you actually care about the characters by the end.
An aspect of this game that is completely unforgivable is the AI. It is ridiculous that this game was supposed to have revolutionary “radiant A.I”. Actually, the A.I in this game is awful. Enemies run in to walls and traps. The conversations the NPCs have are just random snippets of dialog strung together. They go something like this:
"Greetings Nord!"
"Safe travels"
*cough*
"Shut up"
"Hello"
"I saw a mudcrab the other day..."
The “lifelike” NPCs do such things as eat apples, read books, sleep, and sit in chairs. And that's it. Also, guards will kill NPCs if they commit any crime, from murder to stealing a piece of bread (the video is on youtube). Two guards can always be seen near a certain city trying to kill each other over a piece of deer meat. There were both set to gather meat in their schedule. In one quest, you speak to a man in a dungeon. He tells you to follow him, then runs straight ahead, directly on to a trap. It smashes him against the ceiling. If he lives, he remains on the trap, allowing himself to be continuously smashed until he dies. It is ridiculous that such hyped A.I turned out to be terrible.
Altogether, this game does not live up to the hype. It is good, but has little replay value.