Summary: I am a huge fan of the Sonic games in general, but this game was way to frenetic for me. The fact that the game goes between the two screens on the DS as you're moving through the levels makes it very difficult to figure out where you are at any given time.
Conclusion: When I first got this game, I thought, "Oh, great! its got good ratings and good reviews. Quite cheap as well. This has got to be good!" How wrong I was. There are hardly any levels at all, and it is all over and done with in a matter of days.