Well there is a fella who's reviewing the game that's let out a few tidbits. May be spoilers ahead!
1) Naganuma is not involved in the music at all. Teruhiko Nakagawa [ie; Blaze remixer in the original] is listed as Sound Director, and Tomoya Ohtani, Seirou Okamoto, and Mariko Nanba as Music Composers. Not as good as Sonic Rush [expected, really]
2) Despite saying otherwise, Dimps made the game.
2) Game plays just like Sonic Rush, maybe a bit easier and more forgiving. A plus!
3) 3D levels are fun, play very similarly to the 3D Special Stages in Rush, only need to play once to get to a level. This is how you collect 'Emeralds' - Johnny challenges you for emeralds.
4) If you suck at the game you will need to replay some levels. Tails required 'Metals' and getting good rankings gives you more metals.
5) Ludicrous amounts of cutscenes and 'story', but can be skipped for the most part. Marine's a pain in the arse. [spoiler] Sonic & Tails warp to Blaze's world - Whiskers being the Eggman of their world apparently. Nega hasn't shown up yet[/spoiler]
6) Level gimmicks include a 3D rail ride. Nothing slow like Mirage Road [yet]
7) Some enemies require multiple hits, but rare.
8) Wifi - you can race people online, and upload scores to worldwide rankings. Apparently only shows the top 3 players though - I'd imagine the website would show more?
Also, EGM reviewed the game in their latest review - giving it a 7.5, 7 and 7. They gave the first game straight 8's.