Is it perfect? No. Is it a huge step in the right direction? Yes.
However
While the music never really grew on me, the speed certainly picked up once I become more fluid with the game's slightly unusual physics. Areas where at first you may slow to a crawl, you will be able to later dash through with the pure sonic feeling of old.
I'd ask all of those reviewers out there hating this game to take a moment to consider older sonic games. Lets take Sonic 2 for example and compare it with gamespot's review for Sonic 4.
Erratic difficulty? The first boss in sonic 2 was a slowly moving car with a drill on the front that did nothing but go back and forth, while the final boss was a giant robot you had to face back-to-back with metal sonic.
levels that break the flow of the game? How about the chemical plant zone where you constantly had to wait for moving platforms to align or be present.
punishing chaos emerald levels? Do you remember the half pipes filled with rings, where you could get blindsided by spikes at every turn?
I'm not saying this game is perfect, but appreciate it for what it is. Though some of the zone names and styles are reused, and the bosses are retweaked versions of old ones, they did throw in some new inventive concepts as well. Even more than that though, this is a return to form, and a starting point from which they can make bigger strides.
All in all, this is a fun step towards proper sonic form, and one that I look forward to seeing a continuation of.