Maybe a little too big adventure.
Game begins when you as a prisoner receive a visitor to your dungeon: the emperor of Tamriel Uriel Septim. He tells you that his end is at hand and gives you an object. It is your job to locate emperor's illegitimate son and help him to be the rightful ruler of Tamriel. This is the main quest, but aside from that there are lots of side quests to do as well.
Graphics are pretty good when taking into account how huge the game world is. There's nothing that would irritate you when looking at the screen so in that respect everything is in order. Unfortunately the frame rate is all over the map and especially outdoor environments are sometimes slow to play because of the frame rate drops.
Music is epic and orchestrated and at times maybe a little too melodramatic, because the aggressive score of battle kicks in every time a lone wolf comes in your way while walking on the road. Sound effects do their job, but are not really that remarkable either. Best thing is voice acting, which is different for every character and there are many of them in the game. There are subtitles, which makes following the story much easier.
Oblivion's gameplay is from a first person perspective. You can also change into a third person perspective, but this game was clearly designed to be played as first person. You can create a character you wish and do pretty much anything you wish. There's hours and hours to spend in just walking around and talking to people.
Combat system works much better than it did in The Elder Scrolls III: Morrowind, although I have never been a fan of first person sword fighting. You can save anywhere anytime so it's a great way to experiment the effects of your different choices.
Of course in a true RPG fashion there's a deep leveling up system, but it's a little different from what you've used to in many other games. In Oblivion you level up your sneaking skills by sneaking and acrobatics skill by walking and jumping instead of just gaining a new level in all of your attributes automatically.
For me Oblivion was not that interesting in its story and most of all: it has a too big world to explore. But if you are willing to dedicate a lot of time being in the world of Tamriel then this is an RPG for you.