As you know Sonic the Hedgehog has had his better games and his worse games, that means some people question if the Sonic series is good or they just stop playing Sonic games for good. But this game is by far one of the reasons why you should still play the Sonic games!!!
It starts with a cut-scene in which Sonic and Tails are flying in the middle of a storm and a lightning bolt strikes them down and they crash land on Southern Island where they meet a raccoon named Marine who tells them about Captain Whisker and how he is causing trouble.
The positives of this game would have to be the sense of speed you would get, the environments, the awesome music, the humor in cut-scenes, the way of transport to new areas via water-bike/submarine/boat brings more variety to the game and the bosses are epic as well.
the only problem is the cheap bottomless pits but there is less of those now than there were in Sonic Rush.
In short, this is THE platformer and one of the greatest DS games of all time!!!