Very nice, but not the best Sonic game ever.
The stoyline this time is that an Alien named Black Doom has begn invading Earth, and you gotta choose what to do, thats a lot different compared to the usual Sonic games.
Shadow The Hedgehog is a pretty fun game, you have guns, vehicles and a load of other stuff to mess about with. Shadows past is still confusing, with about 13 alternate endings in which to watch, you have no idea what Shadow is and know about as much as you did before...
The graphics are like Sonic Heroes, and have that good feel to them, but the problem is the camera. I never had camera problems in the other games but in Shadow, you'll find yourself cursing as much as Shadow does. The guns are just to add a layer of new things to it, the gun control is annoying and you'll probably be sticking to Homing Attack, the vehicles are just a diversion too.
The levels are great, and include multiple ways of completing the mission: Hero, Dark and Nuetral, all leading through a different path, which gives replayability, but after a while the levels get tedious and you'll be bored going through the same level again and again. This makes completing the storylines hell at points, so this game has to be played in week breaks sometimes, but playing total gametime you'll complete it in about 15-20 hours is you've played Sonic games before. In all the games pretty good, and Sonic lovers will revel in it, and the music is as good as ever! (Crush 40 is perfect!)