Well, now that I've been activated here, I'll just say: it's good to see you doing even more, Lake! That said:
The Spike Shield is fairly bland. Perhaps it would look nicer if it was a translucent silver sphere, with the white streak (maybe add another one too) looping around. Think like an atom.
What was that weird shield that changed colors and then dissipated on its own?
I noticed the Aqua Shield bounces you up as opposed to down (like in BTS) and the Spike Shield (which looks similar to the Lightning Shield) gives you a Stomp. If we get a Flame Shield, it should therefore give Sonic a backflip. It's only logical, right?
Falk, we need more music from you. Always.
I noticed the Badniks are always in places where the player is likely to be moving slowly (right after running up a wall, jumping up from a lower ledge, etc.).
Tails is a really slow flier in this one. He flew rather quickly in BTS, and for quite a while.
Hope I'm able to help ya out here, Lake.