Fantastic as always! As you know I got stuck on a certain level, but I'm definitely planning on giving it another try - the gameplay is just so good and really makes me want to play more. I also love the new mechanics and how well everything is colour-coded (green for extra boosts, pink for portals etc).
I did miss the background music, and I also liked the "mystery" of the previous versions, but that's just a personal preference (not sure if it's just a demo thing but having it explicitly state that you're in hell, for example).
I also thought it'd be cool to be able to "look around" somewhat, i.e. move the camera over slightly so you could plan ahead a little better.
Overall a really great entry and I'm looking forward to the full release!