The possibilities are ALMOST neverending.
I realized something as I read the other reviews for this game: Most of them are so fucking biased against the Werehog I can't help but laugh. That the day stage mechanics are somehow ruined by a completely different aspect of the game, they say. Infact, the very first review I read of it said the game was ruined simply because the Werehog existed. No, fuck the fact that it may not have played badly, it is a horrible idea and the entire rest of the game should be shunned for this.
This game is by no means horrible, although there are afew flaws.
One thing before I start: The Wii and Ps2 versions, while similar, feel completely different from the PS3/XBox360 versions at certain points, mostly in the final levels.
Story:The game starts with, oddly enough, the final battle from an unexplained adventure. At this point, Sonic's already collected the Chaos Emeralds, chased Eggman to his final base, and is beginning to storm it. Sadly, this part isn't playable. After Sonic and the doctor have their fight, Sonic goes Super, and tails Eggman to his apparent super weapon. However, Eggman, in a shine of his 300 IQ, actually set all this up as a trap. He manages to trap Super Sonic, and uses HIM as the power source along with the Chaos Emeralds, firing a cannon upon the earth and shattering it, releasing what is apparently the god of darkness, Dark Gaia. However, it was awakened too early, and crumples under it's own weight, also shattering and spreading across the planet. This entire process has not only drained Sonic of his energy, but the Chaos Emeralds are now simple, lackluster gems. Sonic himself has transformed into the controversial Werehog, and after he appears to be getting ready to put the hurt on Robotnik, he is then "dismissed", and thrown out the airlock along with the Emeralds. He eventually lands on the continent of Apatos, and specifically on a small... thing he later names Chip, who can't remember anything past the last few moments before he was hit. The two band together to recover Chip's memory, restore the Chaos Emeralds, and stop the bumbling doctor's schemes.
So other than the Werehog and drained Emeralds, standard "collect the emeralds and kick Eggman's ass" plot. But it works.
Concept: I admit, even I was skeptical of this to a vast degree. The game is split into two core elements. Day stages, where Sonic races through streets, glaciers and jungles to reach a goal at the end, blazing past and through anything in his way in classic Sonic Style, mainly Robotnik's robots. And Night stages, where he takes a more physical approach to things as he takes on the segments of Dark Gaia that were scattered about the planet similar to how Knuckles would, gaining experience by collecting fragments of Dark Gaia that haven't formed into monsters yet and gaining new moves. The hub worlds are the Gaia Temples, structures that contain the entrances to the levels, bosses, and in-game puzzles where you're able to unlock bonus content. The game is based off a modified version of the engine used in Sonic and the Secret Rings, rather than the Hedgehog Engine.
Reality: The game turned out vastly better than I expected, although the flaws transferred to different areas. The Day levels play excellently, although the Difficulty curve takes a spike at the final level. However, the ranking system is exceedingly brutal, relying only on time, meaning those striving for an S Rank are in for a rough ride.The Night Levels, although not perfect, were nowhere near as bad as people make them out to be. The major problem was how the Werehog had only two movement settings:Run and Run faster. Getting him to move at a decent speed to traverse thin platforms has fucked me over at times. There's also the mechanic of collecting Dark Gaia seals to clear some barriers. While it was a decent challenge finding them, it like this was there just to make the game last abit longer. The combat was handled well, and it's fun to just go postal on the enemies, especially with a move gained later aptly named "Beatdown." The ranking system for this is less cheap feeling, measuring time, rings and enemies beaten rather than just the first one.
Game cutscenes, instead of being in-game, are actually video files from the PS3 and 360 versions, eliminating the lag issue i've been hearing about. Speaking of which, the framerate is extremely consistant, with the only actual chance of lag being in the last leg of the game thanks to how fancy it can get, and even then I only ever got about one framerate drop in my first playthrough. The bonus puzzles are challenging, to the point where I'm still working on afew. The also ripped on lack of two worlds doesn't really feel like that big of a loss to me, oddly enough. The quicktime events aren't as numerous in either Day Or Night, but the sequences for the Werehog tend to be flat out awesome.
Graphics:The graphics are excellent, mainly in the character design. Sonic and friends don't look misproportioned, and the enemy design is flashy, yet threatening. However, the levels look abit bland and generic at times, mainly in the jungle based levels. The graphics for the final level, a mix between a themepark and a foundary I like to call Hell, can actually screw with you at some points, since it becomes difficult to tell the ground from the bottomless pits at such speeds.
Music: The soundtrack for this game is excellent. The main themes, World Adventure and Endless Possibilities, turn up in afew forms. The only truely badly done bit of music is the E Rank results music, and it was really just adding to the game's humor considering it was meant to be bad. However, the Spagonia themes were abit lackluster, in my opinion, although it still has an appealing flare.
Overall: I'd recommend buying it if you want fun, but challenging gameplay. The PS3/Xbox360 versions may be even better, although I can't judge that due to lacking both those systems.