Sonic Generations - S Ranks & No Skills - Part 003: Sky Sanctuary Zone

Probably the biggest difference in quality between two acts for me.
Act 1 feels really smooth, especially if you've mastered bouncing on enemies to cross gaps. The Egg Robos line up well to give you the opportunity to take shortcuts. The hanging platforms and cloud bouncing work really well too. The Death signs from Sonic 4 are here, and they're still kind of obnoxious.
Probably my favourite of the Act 1 levels. After this Classic Sonic wasn't in any of the games, so expect a lot of added gimmicks to try and fit him. Some land, some don't. Same goes for the music.
Act 2 is probably my least favourite Act 2, conversely. It's mainly the 3D sections that feel off on this, so a heavier focus on 2D which Modern Sonic doesn't excel in makes this one not as enjoyable.