The best Role Playing game I have played. Immersive, entertaining, challenging, and inventive.
I had purchased the original game and as DLC was released I purchased all of it. (Yes, even the horse armor.) I have obtained every achievement in the game except for 3. (2 thieves guild achievements and 1 shivering Isles.)
Starting the game (back in 2006) I could not consider myself a very good gamer. I was into Halo and some Snowblind studio games of hack n' slash from the last generation of consoles. Jumping into Oblivion was a bit overwhelming to say the least as there was just so much to learn about the advanced menu system , and all of the books and things I would find in my journeying throughout Cyrodiil. The music was great and the leveling system was good. I played through the game with an Argonian as he could swim, breathe underwater, and was resistant to most poisons and diseases.
Of all of the DLC content the Shivering Isles was indeed the best DLC I have played in any game. I was thoroughly entertained and had a blast wandering throughout the world looking at all of the unique flora and fauna.
And even with all of the achievements there is still a TON of unexplored territory, house, ect…
This is the game that keeps on giving. If you have the dedication and are willing to be immersed in a world and game that will take you a long time to see everything. Then You can ask for no more than Oblivion. It was a great experience.