Hard to start, and gameplay wears on you before long, but the fun of questing will long outlast it.
As of April 2010, I still haven't reached the halfway point. This game is, well, long. In terms of length, call it Ben Hur times fifty. I always go into the game with the intention of leaving no dungeon unexplored, no dialogue chain unwrung. After a few hours, I figure screw it and pop in Halo, but this time I decided to turn the difficulty to piss-easy and beast through every quest as though I had a life to return to.
Let's break this up into a few categories to make this interesting.
--CHARACTER CREATION--
The Bethesda guys created a dynamic gameplay-style-detection system for the sewers, but then they fed it to a hungry guinea pig and created the version the game ships with. After the Emperor's assassination (SPOILER ALERT!) Baurus, after completely ignoring the fact that he died alone with you, this other supposed assassin, and no witnesses, tells you that from what he sees you're an experienced such-and-such, because apparently he can see through walls. Of course, you're not going to want to use any of the default classes unless you're mindnumbingly stupid, so you'll want to create your own class. A for effort, but I'll have to give a D for results.
--MUSIC--
Jeremy Soule's epic score sets the mood perfectly... for the first ten hours, then it'll start haunting you in your dreams. For a game that can easily go for a hundred hours if you want to finish all the sidequests, the music is incredibly limited, clocking in at about an hour. There's a remedy for this: hop into an Oblivion gate and play some Slayer. Which brings me to...
--OBLIVION GATES--
There are 60-odd unique Oblivion planes, or so I'm told, which is funny because by my count there's one. The strategy is always the same: Find your way to the big tower, climb to the top, grab the sigil stone, win. Fun for the first two times, then you'll get bored. Sure, you can enchant stuff with them, but enchanted weapons and armor suck until you reach journeyman level in armorer and can actually repair the damn things. And besides, once you reach the arcane university you can enchant anyway with the gold you'll be rolling in from all your looting.
--DLC--
Shivering Isles and Knights of the Nine are huge fun, and I'd recommend them. Then there's crap like Battlehorn Castle, Frostcrag Spire, Deepscorn Hollow, and Dunbarrow Cove. It's nice to have those as quick access to the services you'd otherwise need to progress through the guilds to get, but honestly why pay extra money for them? And don't even get me started on spell tomes and horse armor, the DLC that should have been free.
--COMBAT--
If you like repeatedly pressing the same button over and over, than you'll love this. There's little to no strategy involved, but at least the magic is fun.
--MAGIC--
Oh, no it's not. Every single spell can be achieved through some other means. There are spells that heal or aid you (potions can do that), inflict status ailments on the enemy (poisons), lifting objects from afar (tilting that analog stick forward just a bit will put you in carrying range), charm people (just speechcraft and bribe your way to being loved) and finally, deal damage (there's a wonderful invention to do that. It's called a sword.) Plus it takes for-freaking-ever to switch spells. Here's a tip: stick to your swords, crank down the difficulty to piss-easy and blast through the game. You'll receive absolutely no penalty and the combat becomes less of a tedious mess.
--LEVELING UP--
You know how when you kill enough baddies in an RPG you level up? That's great. Nothing's wrong with the system... it worked back then and it works now. But Oblivion has an ass-backwards way of doing things. Whenever you do ANYTHING in the game, your skill in whatever it is goes up. When you've done that enough times you level up- but that only works with your major skills. By major, I don't mean the ones you use the most, but the ones you picked at the beginning of the game. Remember when you actually thought you'd be majoring in alchemy throughout the whole game, then found out your potions were useless even when you leveled up a bit? You still need to make potions for no reason but to level up. Here's my advice: put a major skill on athletics and instead of fast traveling, walk everywhere. You'll be leveling all over the place. In a move highly reminiscent of New Coke, Bethesda went back to the "classic" style of leveling for Fallout 3.
--VOICE ACTING--
The voice actors are incredible, but there's just too few of them. I count at best seven unique voices, only two of them female. They had Sean Bean, they had Patrick Stewart... why didn't they use them?! I remember once I literally heard two separate characters say the exact same thing at the exact same time. I got "well met" in stereo. Even line recordings are recycled between characters, meaning some of them completely change dialect mid-conversation.
So why did I give this game such a high score? The answer is simple:
--QUESTING--
That's what this game is all about. The story may not be much to talk about, but it's just so involving to finish all those quests. The guilds are a joy to progress through, the main quest is great, and with the the occasional scavenger hunt quests (I HATE NIRNROOTS!) everything is fun.
So if you have the patience to get through sketchy gameplay, don't want to pay for an MMO, or just want to return to the glorious days of tabletop RPGs, pick up a copy of Oblivion. Or, if you already have it, I hope you enjoyed this hate rant, inspired purely out of love for the game I am bashing.