I began this expansion recently though I have owned Oblivion since year 1 of the Xbox 360's existence. This expansion also is packaged with the Nights of the Nine expansion, but I have not yet attempted any of that expansion. The Shimmering Isles is an enjoyable expansion that remains true to the Elder Scrolls storyline. After installing the game, you play with your Oblivion disk. After 24 hours of in game play, "a strange door" quest opens. After installation, you can simply rest for 24 hours to begin the expansion by traveling to the strange door. Though the expansion story does not affect the main storyline in Oblivion, I recommend that once you begin the Shivering Isles, you stay in that world to keep the strange feeling and pace of its storyline, even if you have not finished Oblivion. Why bother closing Oblivion gates when you can stay on another Daedric Plane? So, before you enter the strange door, come in as if you are never going to leave. You may not.
yes: I recommend this product