A complete flop to the crowd's expectations.
Back camera problems are to be expected in the Sonic Adventure series, though the original Sonic Adventure series had some replay value and plot backbone. Shadow's story seems almost thought up off the spot and almost dead typical villains. The villain is your typical black bad guy (this one's an alien) who's got an english voice actor that makes you sick. Which brings Shadow to one of its other main problems. The english voice acting is very second rate. Sonic's original voice actor has suddenly dissapeared out of nowhere, which is immediately noticable when you go into the first level. If you play it, play it with Japanese dubs.
Shadow continues the sonic tradittion of attempting a highly replayable game that has to be mastered in order to unlock the secret ending. The only problem with this is you have to be a very determined Sonic fan to sit through the game through every possible path Shadow can take in order to get the secret ending since the gameplay is far more annoying than fun.
If you are a determined sonic fan, rent this game before making the decision to buy it.