Rough first impressions:

It's beautiful.
Enemies are really cool.
I found the second Emeraldus level easier for some reason.
I freaked out when jumping off the ramp at act 2, started falling back and the screen started flashing mid-way. I fell into some pit but I still got transported to the boss.
Marbelava is kind of glitchy, I had to die in act 1 because falling blocks all fell into the same spots in lava and wouldn't budge and I got hurt numerous times because the swimming blocks and spiky platforms lagged.
The second act is a bitch of a level. Still can't beat it. I found a secret area by falling into lava, and got stuck in a wall in a corner when I thought it's a way back (maybe it was). Well, I never liked Marble Zone in Sonic, so I guess it's only fitting. Looking forward to getting to the further levels, then.