For a flipaclip animation, I thought this was going to be the worst thing I had ever seen, especially as a sonic fan. It seems you have subverted my expectations, this is actually pretty good, even for a flipaclip animation. The only real issue I have is parts like 0:42 and 1:47 where all the background is happens to be black with some thick red lines over it, maybe put some glitching effect over that or something (if you're able to do that). Furthermore, Sage's fingers at 2:29 seem to be a little too big when compared to her actual design, she's meant to represent a small child after all so it would have made more sense to give her slightly smaller, more dainty hands.

So, recap; this doesn't suck, there's major room for improvement (if you wish to improve, that is), I'm surprised you did this in flipaclip instead of in something like flash and I hope my above critique hasn't discouraged you.