Too much hype & expectation is where this title went wrong.
Fast-forward to today, Sonic titles have been released on multiple platforms with very mixed reactions. Most negative, and for good reason; many of the titles where a bit ambitious, or just didn't seem completed for many reasons. Sonic Unleashed was marketed as a "repair" to the lackluster titles of recent, and was said to be a step back to the franchise's earlier roots. This is where things started to promise disappointment; it resulted in too many people making comparisons to the pinnacle of Sonic's history. The worst part of this was the fact that a gimmick was added to the game, radically different from the franchise's classic roots.
That's just my analysis as to why this game is so negatively received. It's my goal to make this a review of the game itself (Xbox 360 version), not a comparison to the franchise's games of past.
The first thing you'll notice are the visuals, this is one of the game's strongest points. The animated fmv shown in the opening of the game is truly remarkable, and sets a good impression of what the game has to offer visually. In game the character models are clean, and defined. The animations of these models are impressive, and adds to the overall feel of the game. The stage environments are also well-done, and give a good taste of the various locales around the world they're based off of. Bright colors are used mostly used for the characters, but are handled nicely by the contrasting environments many of which use more browns and grays for coloring. There is some clipping in a few parts, but it's very hard to notice and isn't overly distracting. Slow-down is evident in some areas, especially the nighttime stages where there are large numbers of enemies on the screen at once, this can be a bit distracting but doesn't tend to take away form the game play.
The audio stands out as well. The music consists of orchestral scores which tie in nicely with the world adventure theme the title has. The sound effects vary in quality. The environment sounds are solid, what seemed to stick out were the sounds that were made when you interacted with the environment. Some of the decorations you bump into or attack in the stage seem to make odd sounds. Take breaking down a door; it's awfully muffled considering you're snapping wood. Overall the sounds are very light-hearted and cartoony, which works with the light nature of this game.
The story isn't anything special. The world gets broken into pieces by an evil doctor, and during the process he transforms the protagonist into a werewolf-like beast. The act of braking the world unleashes a creature of great power whose evil is spread throughout the broken planet. It's up to the protagonist and his friends to save the world. The story is fine, just don't be expecting novel qualities. It can be compared with a Saturday morning cartoon.
The game play is essentially split into three sections: The hub-worlds, the daytime stages, and the nighttime stages. The hub-worlds are a stage-select of sorts and let you interact with the residents of the area you're in before you head to an action stage. These characters provide information about your quest, and sometimes provide opportunities for quests. Many of these quests are simple fetch quests which are completely optional, they have nothing to do with advancing the game's storyline and can be frustrating due to the lack of warning and cues. The daytime stages are fast-paced action stages where you find yourself blazing through levels at amazing speed. The camera seamlessly changes from over to shoulder to a more side-scroller point of view, which adds variety. The difficult part about these levels are the areas where the camera goes behind your character's shoulder; It's hard to maneuver successfully due to the speed you're usually traveling at. You get used to it after a while, but it can be frustrating at first. The nighttime stages are much slower in nature and are much more platforming and combat heavy. The combat is a simple beat 'em up styled system with a fair roster of moves and combos to pick from. These combos are fairly easy to pull off and only require you to push face buttons in a certain order. The platforming is solid, if not a bit uninspired. Some areas are very streamlined and basic, whereas others feature simple puzzles and take a bit longer to progress through. These two styles of game play are very contrasting, but provide variety.
Overall, I was impressed with this game despite some flaws that were present. If you pick up this title with little to no expectation, you'll probably enjoy on some level or another. It's a solid platformer with great production values and a lot to do.