The whole world and the 100+ hours of gameplay may seem intimidating at first but after a while you get a feel for it.
The game's graphics are nothing short of amazing. The whole game looks very realistic. The character models look great from afar and up close. The medieval buildings are big and awesome. This is one of those games where you can stop and watch the setting of wherever you are. Since you spend most of the game in towns/cities you will notice that all the towns look unique and have their own lifelike people.
Oblivion's sound is also very appealing, though not as much as the graphics. All the characters have voices are fun will all introduce themselves to you and talk to you about random things and thier voices sync to thier mouths with overall great dialogue. The problem is, sometimes you don't hear the voices at all. You also hear the same voice on different people. This didn't bother me at first but after a while it got annoying. these are problems that you will notice but overall they are forgivable.
The gameplay is very fun and fast for an RPG. You play the game in first person and use things like magic, or a mideval weapon(such as a sword or bow). These all work, and like any other RPG you will choose classes that specialize in one of the three categories:magic, stealth or fighting. So you could a mage, a warrior or a thief(The classes go deeper, but that's the main part). Even though there are classes you will end up becoming a hybrid of all three(it just depends on what you will use most). They are all fun to play but there is some unbalance in the classes. The specialization magic seems to go alot deeper and be more useful and powerful than the others. It almost seems like being a magic spec will beat out all of the other classes if you know what you're doing. Oblivion has a great and refreshing way of leveling up you character. You level up by leveling your skills rather than just killing things. So if some of your major skills are repairing armor and talking to people, then you could level up by doing that. Another good thing about Oblivion is no matter what, the world will scale to your level. You could do anything at any given moment, and there usually is no level requirement. A bad thing about the world scaling is soemtimes the scaling doesn't seem right. Sometimes situations seem too overwhelming if your a little higher level. Well, if you find yourself stuck at any given time you can change the difficulty of the game. This may seem like a cheap and cheating way of getting through the game, but it may turn into a useful tool if it gets too frustrating to you. Overall I like it in there, even it does make you feel guilty using it. A problem with the gameplay is some AI problems, sometimes the enemies/allies with run into walls or make themselves immovable. This is gives you another kinda cheap advantage if you know how to exploit it.
The game has a good story to it. It's pretty simple and it's pretty much what I said above and it's not as long as everyone says it is. As well as the main story there are many different factions to join such as the fighters guild, the mages guild, thieves guild, Dark brotherhood(assassin's guild) and Arena. All of the factions are very fun to play and have thier own engaging story to them. You can also help random people and their problems. These quests are all over the world and can be pretty fun to do. Oblivion does suffer from the problem that most RPGs suffer from in that alot of the game's quests are fetch quests. You will find it throughout the game(particularly in the faction and main quests) but they are never too annoying and are fun to do. Most of the quests require a lot of travel, which isn't always a bad thing. there is a thign called fast travel in which you can travel across the world in seconds. This gives the game an overall quicker pace.
Overall Oblivion is one of the best Xbox 360 games out there. If you're like me and didn't like Morrowind you may still like Oblivion. Some say Oblvion was dumbed down but I disagree, I think Bethesda perfected the style of the Elder Scrolls series. Oblivion is the kind of game you'll probably end up spending hours at a time playing. I would reccomend Oblivion to people who like RPGs or like games that can get kind of slow at times. To sum Oblivion's experience up, its a game that depends on how much you put into it. If you're looking for a game with quick and intense thrills that you will only play for a little while, then Oblivion is not for you, but if you spend time and play Oblivion the way it's meant to be played, then you will find a rewarding experience that you can't find in almost any other game.