Don't think. Just watch.
I like everything, really, this is the hack which I like more. But mix sonic speed with platforming is very difficult work, so, I suggest Add different enemies or events, since Megamix Team is even innovating the bosses, new Layouts are already done, as the ramps never seen in Marble Zone, ok, but the limitation of events, and excess of speed may make the game look like sonic advance 2, which would be a waste. To me, Sonic's speed is just a caracteristic from the character, but is not the big differential of a classic gameplay, for example, Sonic 1 was much more platforming than speed, and was the game which turned "Sonic The Hedgehog" a instant classic. The new 2D games as Sonic Rush which are focused more on speed, are not bad (The Tension Gauge was a great idea), but sure are not better than the first ones of 90's.
PS: I am not programmer, so, I just said somethings which would like to see in my own hack, OK? Keep it up!
Ah, "Finish-him!" should be cool add in the boss too