My mate bought me this for my birthday recently and I must say I have really enjoyed playing through it. Story is basic, you have to save the world, which Eggman has split into pieces. Each piece needs moving back into place before Dark Gaia (Big nasty evil earth elemental thingy) gains enough power to finish the job Eggman started.
The game is split into different stages. Speed stages are played out during the day, and these are fantastic. You control Sonic as he runs, jumps, rail grinds through the levels at awesome speed while collecting rings and avoiding, or destroying any nasties in his way. The first two levels throw you into this right away, and are both beautiful. So much so I must have played the second act a million times (My record is 2m:18s and an S ranking).
The game isn't all about speed though. At night Sonic transforms into a Werehog. He gets stronger and slows right down. So the game then plays out like a very limited God of War. You kill enemies with combo's and have to jump on platforms, balance on beams and swing from poles with his now stretchy arms. These levels are fun enough but sometimes very frustrating.
I'm going to warn you now that the difficulty on this game borders on unfair. The later levels are designed to hold you back with some very nasty tricks. If you see an extra life in this game, it usually marks the start of a tricky section where you will die repeatedly. During the speed stages you will quite often run into an enemy or set of spikes or fall into a pit the first time you play them through. Then expect to fall for the same thing again and again until you figure out a way round. Sometimes it's not so obvious where you are going, especially when the speed stages rush past you. Also expect the same for the night time stages. Which are probably worse for this kind of cheap trick. You will have to fight your way past monsters, swing on poles above nasty pits of death and then kill more enemies only to die while balancing on a beam, which will take you back to a checkpoint where you will have to do the same thing all over again! ARG is the word you will be looking for. Don't even get me started on the last Eggmanland stage, which has you switching between Sonic and Werehog to get through the level. Probably the hardest level I have ever had to complete in a game. My time for completing that was 65 min. I have since got it down to 25, but only because I ran away from most of the nasty fights!
So you're asking yourself if it's so frustrating, then why buy it? Well, how many games these days are easy? Most games don't offer much of a challenge. Sonic Unleashed is old school platforming. It's not perfect, but for those willing to give it a try and practice the stages until you master them, there is a cracking game here!