Definitely looks like it controls more fluidly than Generations, and the acceleration will definitely help stave off the sluggishness that Classic felt like he had in that game. The bouncing off of enemies being more variable also looks like a good change, though it's hard to tell how much input has to do with it since there are a lot of wonkily aimed jump attacks. It's hard to comment on the level design but it doesn't look completely doom & gloom.
The song isn't really bad as it is a strange fit for the stage. When it gets
really melodic it rather sounds like it's from a carnival-ish stage, or an instrumental rendition of a vocal song, than Green Hill. Either way, it has a really good energy; not sure what's up with the audio mixing near the end though.
Still pretty interested in seeing what this game does, but I can agree that Green Hill verbatim is a bit tired (though for the sake of this game's plot, probably necessary).