I thought I would throw another Oblivion review out here due to my perspective as someone new to the RPG gaming experience.
Oblivion is a difficult game to give a straight forward rating due to it's sheer complexity.
From the very first when starting a new game you are immediately swept up by the graphics, theme music and narration (by Patrick Stewart of Star Trek: TNG and X-Men fame) of the introduction. At the beginning you are "deposited" into the Imperial prison for an unknown crime, are given your initial character creation choices and then from there the action takes a couple of odd twists; one, coming into contact with the Emperor himself and two, being entrusted with a crucial mission by the same said Emperor. You will make your way out of prison encountering various objects and obstacles in a kind of subterranean "training course" on the operation of the game controls. This basic training is welcomed due to the relative complexity of the gaming yet to come.
Once you exit the prison the vast gaming world literally opens in front of you and you are given the choice through a text message that you can either pursue the main quest or go off and explore on your own. The latter is very highly suggested by this reviewer.
If anyone is first starting the game I would suggest pursuing exploration and side quests for at least the first 10-20 character levels before attempting the main quest as in my opinion that is the climax of the game. I am on my second run through the game; on my first I ran straight into the main quest after only achieving a character level of 5 and found the game combat much too difficult to be enjoyable. In this my second run through of the game I am currently on character level of 29 and am still pursuing the many miscellaneous quests available throughout the game, many of which I never encountered in my first run through it. I'm not sure when I will attempt the main quest or if the game will force me into it after a certain period of time, but I can tell you that the playing experience has vastly improved for me from my first time through.
I've found that the character levels 16-23 to be the most difficult. The game introduces new creature obstacles as you level up, some of which level up with your character and present considerable challenges even to high level experienced characters. Some of these creatures you will find an easy battle, knowing exactly how to eliminate them from your path. Others you will learn to dread even avoid knowing full well, that the encounter will lead to the exhaustion of your health potions, armor and a sore gaming finger