Oblivion is, quite simply, the best game I have ever played.
Let's start with the gameplay. You have a massive world to explore and several towns and cities. There are over 300 locations for you to discover (mines, houses, forts, ruins etc.) You can choose between four main combat techniques; sword; magic; bow and arrow and blunt (axes and hammers). Or, you can just use all of them if you like. That's what makes Oblivion so great, the fact that you can choose how you want to play the game. You can choose between many different races to play as, ranging from Bretons, Nords, Khajiits (lion-people) and many more. There hundreds and hundreds of items to collect; swords, gems, stones, and many more. With the gold you get from your adventues you can then invest into a house and decorate it with your prized possessions! You can choose your characters major skills (7 of them) and when you level any of them up 10 times you level up overall. The major skills range from- blade, destruction (magic), restoration (magic), marksman, illusion (magic), armorer, light armor, heavy armor, alchemy and many more. So you can make a character depending on your gameplay style! You can choose to play in either first or third person but the game was made for first person so that is the recommended gameplay style.
The main quest, which I rarely do, consists of demons from Oblivion (a hell-like reality) coming through Oblivion gatea and into the world. It's your job to take down the cult that wants to achieve this. Personally, I never tend to do the main quest. It is fun on your first run through, but the game has so much more to offer. For example, you could join the four guilds (Mages, Fighters, Thieves and Dark Brotherhood), just wonder around collecting loot and doing side-quests (my favourite) that NPC's ask you to do. The quests are very diverse and fun.
The graphics on this game are stunning. Although you will probably encounter a bit of draw-distance issues you can forgive it as the graphics are so wonderful to look at.
The controls are easy to grasp yet not too simple. You can hotkey spells and weapons for quick, easy access keeping the game fast-paced. R1 is to attack with a sword, R2 is to use magic, L1 to block, triangle to jump, X is action.
Overall, Oblivion is a masterpiece that should never be missed out on. It's my favourite game and the game that I have spent the most hours on. Buy it- you won't regret it!