I started playing Frontiers Revisited (Kronos). I don't know why it made me play through the tutorial area that has barely any changed, but after that it becomes more interesting. I like the expanded Cyberspace stages, and the open zone seems more challenging. They tried to recreate classic/Adventure style item boxes and elemental shield, which is a neat detail that I like seeing, but I don't know how much it adds. Instead of the overpowered Spin Dash (maybe it can be unlocked like in the base game) there is a dedicated roll button. I don't know why they kept the Drop Dash, it seems so redundant now.
The controls are an issue though. I find it hard to get Sonic to go where I want, it doesn't feel very precise. Maybe I just need to get used to them