Oblivion is one of the few 360 games that a lot of people still haven't stowed away since its release, and for good reason. Though by this point, the most intrepid explorers have put a couple hundred hours toward exploring every nook and cranny of the land; they've worn it all, seen it all, and killed it all. That's why this is the perfect time to pony up the Micro-bux for Bethesda's expansion, Shivering Isles: a brand new 30+ hour addition to an already hefty experience.
Shivering Isles is a great showpiece for how an expansion should be done. Rather than simply adding new story elements, items, enemies and quests, Isles opens up a world that is aesthetically alien from what you're used to in Oblivion. Purple skies drape light over colossal mushroom overgrowths, crystals jut out of the ground - it's a fresh look that you'll want to spend some time admiring. Each step you take seems to force you deeper down the hole; further along the path of insanity that must have driven every single person in the Isles completely bonkers. Before you know it, you're knee deep in the middle of an impending conflict, spearheaded by the overly demanding ruler of the mad world, the daedric prince Sheogorath.
Shivering Isles is a great showpiece for how an expansion should be done.
Like everyone else in the land, Sheogorath isn't quite all there. His castle lies on the dividing line between the land's two realms, Mania and Dementia. On either side of his throne room stand the appropriate manors representing the two very different areas, one governed by a duke and the other by a duchess. A lot of the choices in the game hinge on the disparity between these two realms; to put it simply, they each cater to their own brand of crazy. In some cases, the land of Mania may provide an option that seems like the "easy way out," or vice versa. It's things like this that make the quests worth reloading and attempting in more way than one.
You won't just be doing all the extra footwork for achievements, either. The story will, for some, be even more engaging than the full game. It's brimming with imagination and the attention to detail that's expected of Bethesda's series. While one may argue that only those well-versed in the world of Oblivion will get the most out of this new tale, it's also not something that was created to alienate new players. Heck, if you don't want to get your old character's hands dirty by exposing them to this unique brand of insanity, just start up a new guy and head for the portal!
The missions here are varied and rarely dull. Where one might have you torturing unsuspecting adventurers as they attempt to explore an underground area littered with traps, another will stall your progression unless you're high on a strange drug extracted from the cave's insects. The general insanity of the locals carries over to each task, especially the side-quests assigned by the townsfolk. In one instance, a typically paranoid man wants you to kill him, but he doesn't want to see it coming. Objectives like this are showcases of the game's many moral dilemmas (though you'll probably have no qualms with offing most of these loonies), and your actions in the main storyline occasionally carry some interesting consequences.
The only real drawbacks here are those that are already prevalent in Oblivion itself. Dungeons and caves can be a drag sometimes, becoming repetitive and bland the deeper you delve. The AI of partners you may have is also pretty limited, which can lead to some awkward moments that hinder advancement. If this was never something that bothered you in the full game, however, then you shouldn't have any problems with Shivering Isles.
What you end up with is a fresh and imaginative new realm to explore - one replete with strange NPCs and even stranger enemies - and, let the cheers of the gamerscore hungry resound, new achievements to unlock. The scope of this package is impressive, and while Sheogorath's main quest can be completed in a modest amount of time, those getting the most out of Shivering Isles will be more than happy to stop and smell the roses, read the books, and complete the side-quests for a truly robust experience.