It's not often that I can be bothered to write a full review of a game, but given that I've bought this game both on PC and Xbox 360, and clocked up somewhere around 70 hours playing time between them, I thought I might as well.
It seems a long, long time ago now, but the game begins with a totally clean slate for you. It doesn't impose any crappy back-story on your character, all you know is that you're a prisoner in the Imperial City Jail. You've no idea what crime you were accused of, your personal history, or anything. And your only visitors (Patrick Stewart of all people) don't really care, they've got more important things on their mind, and they conveniently leave open a secret passage in your cell, letting you know you're free to go, provided you keep out of their way and don't endanger the Emperor, who's busy scarpering (that's the Patrick Stewart character). The escape through caves and sewers serves as the game's tutorial, but at the same time every action you make is noted by the game and used when it comes to the point where you have to choose your character class. The game tries to suggest the most relevant class based on the things you did, but chances are, it'll suggest you be a "bard", given that you probably did an even share of everything. Obviously, you're not restricted to this, you can choose any class you like, or even make your own custom class by picking your own attributes specifically. Once you leave the sewers, that's it, your class is confirmed.
Once outdoors, it can be quite overwhelming for someone new to this type of game. Basically, you find yourself with an entire province to explore, and basically do whatever the hell you like in. Just before you leave the sewers you're given an item and told to find a specific person, and that's basically your first objective on the main storyline quest. However, you're actually free to completely ignore this, and go off doing whatever the hell you like. The main quest is always there whenever you want to continue it, but if you were to just follow the story rigidly, you're probably missing out on about 90% of what the game has to offer. Besides the main quests, you'll get one-off quests given to you by people you speak with, which can range from trivial to time consuming, and then there's also other more structured storylines, which come from joining various factions, such as the Mages' Guild, Fighters' Guild, Dark Brotherhood (Assassins), etc. You can even gain a new quest simply by being in the right place at the right time. NPCs will get into conversations with each other if they pass in the street, and sometimes overhearing a conversation between NPCs can kick off a quest.
The stats system I believe to be the best of any RPG I've ever played. First of all your character has various attributes: Strength, Intelligence, Willpower, Agility, Speed, Endurance, Personality and Luck. Each of these governs a group of skills (with the exception of Luck, which just affects everything you do). Your skills are either based on combat (Blade, Block, Heavy/Light Armour etc), magic (Destruction, conjuration, mysticism, illusion, etc) or general mischief (sneak, speechcraft, security etc). Your character has a "level", and to progress one level you must increase your major skills ten times, which can either mean advancing all your skills or just increasing the same skill repeatedly. As you go up a level, you can then increase three of your attributes, but you get most benefit from increasing the attributes that govern skills you've been using a lot recently. For instance, if you've been doing a hell of a lot of conjuration since you last levelled up, selecting intelligence to be increased will probably mean it goes up by about 3 or 4 points rather than just one, in an attribute whose skills you've been neglecting. What this basically means is you get better at the things you invest time in, which is a natural progression of your character, and makes far more sense than other RPGs, where you simply gain "XP" and get to spend that on whatever the hell you like, even if that's something you haven't used for weeks.
Now at some point, you're going to get into a fight with someone. You've got a variety of choices of how to respond to this. You can go for the brute force approach of slashing them to ribbons. You can hide in the shadows long before the enemy has seen you and take them down with a bow and arrow. You can conjure up an undead or daedric creature to do all your fighting for you. You can simply leg it and hope you can outrun the enemy. You can cast a spell on them which sends them running in terror. You can... you get the idea. There's a LOT of things you can do to manipulate other characters in the world, whether they be friendly or vicious bastards determined to bash your skull in. The effectiveness of the action you decide to take depends entirely on your character, and what he's good at. If you're weighed down by a ton of armour and your athletics skill isn't up to scratch, then doing a runner like a big girl's blouse isn't going to get you very far. If you're a mage with little or no armour, it's not a good idea to go running up to a Daedroth and start slashing away with a tiny dagger, you'd be far better off summoning up a creature to take the damage while you stand further back tossing fireballs over its shoulder. Combat has been vastly improved since Morrowind (i.e. Elder Scrolls III). It's hard to say precisely what's changed, but everything just seems far more satisfying, and there seems to be far more skill required. For one thing, Morrowind had a confusing concept that you could actually swing a sword at someone and consistently miss, despite the fact that they were stood right in front of you, which was due to your sword fighting skill being rubbish. In Oblivion, if swinging your sword looks like it should hit the enemy, it does. Your stats greatly affect your effectiveness still, but not to the point where things inexplicably fail altogether.
I haven't even mentioned the graphics, which incidentally, are incredible, and that's all I'll bother saying, you can see from screenshots all over the net. The atmosphere of all the locations is spot on, from dark dungeons and caves to friendly towns and cities. There's the option to fast-travel between locations (you see a loading screen, the game simulates some time passing and then you're there), but my personal preference is to walk between locations, since you tend to discover all sorts of things on the way, especially if you're the nosey type who wanders off the beaten track. The sense of exploration is one thing that I found massively lacking in World of Warcraft, which is, despite being an MMORPG as opposed to a single player only RPG, a very similar style of game. I never felt the world in WoW was interesting enough to make me want to explore. In Oblivion, just walking down a path, I'd get a sense of curiosity and think "I wonder what's just the other side of that hill over there?". I'd go take a look and there'd be something like an ancient elven ruin, which has nothing to do with any quest that I'm on, but still I get to urge to have a "quick" look around, which inevitably ends up being an hour's exploration where I find numerous incredibly cool things. That is something that is sadly missing from WoW, since everything in WoW is too focussed, and despite the fact that the game tries to promote freedom, like Oblivion, it in fact simply punishes you for not following its quests. There's no benefit to be gained from going somewhere if you don't have a quest there, in WoW.
As for my personal opinion on Oblivion, I'd say it's quite easily one of the best games ever made. I've always liked a game that I can really get into, I'm not much of a fan of that "casual game" crap, and Oblivion is exactly what I was hoping for since the moment it was announced. It came seriously close to replacing Deus Ex as my personal "best game of all time", but just about didn't quite, although I can't rationally explain why. Oblivion certainly comes a very close second. If you've any interest in "proper" RPGs, large scale storylines, and you don't mind investing a lot of time (a very worthwhile investment all the same), then this is the game for you.
10/10