i hate to state my opinion, but i feel like i have to.
i feel like it's gotten worse.
well, i like the new stage, but that's pretty much the only improvement i see.
for one, that vignette when you reach top speed gets pretty annoying. vignettes have usually gotten on my nerve because sometimes they're used when not necessary, or that they make me want to rub my eyes; i'm usually used to vignettes being a warning of something happening to me, but usually just pain. the speedy vortex effect gets annoying, not only that it comes on so suddenly, but that it alarms me too much. i'll be running around at the speed of sound when it suddenly comes on, then "ohgOD OH GOD WHAT'S HAPPENING-" oops spike ball
it happens too often. if it was at least more transparent it would be a bit better, but tbh, i just don't like it.
secondly, the graphics seem... meh. everything is scaled too oddly that it just looks bad. i know, it's so you can see more and have a better reaction to obstacles. but look at Generations:

look at how Sonic is pulled back instead of the camera being pulled back. this would be a better option than raising the resolution because the sprites would look fine, and the player would still have a good amount of time to react.
that's just my two cents on r0036.
again, i really hate having to be negative, but it's for the good of progression.