To me, it's a very short level if you know what shortcuts to take before the snowboarding sequence.
Hopefully, they don't bring back Carnival Night Zone.
That zone made me furious being that back in the day I wanted to get to Ice Cap and Launch Base but could never get past that spinning barrel in act 2.
I bet, remaking it as a 2D level, they would put that in there and would probably cause a lot of anger to a new player who hasn't played Sonic 3.
EDIT:
@Serephim: The only thing about Hydrocity being remade that interests me is the act 2 track. Very catchy.