I'm surprised by the SSZ negative opinions here. Act 2 isn't one of my favourites, primarily because of how short it is. The layout is fun though. But Act 2 is fantastic; it's one of my favourite levels in the entire game. I adore everything that the stage to offer. PGZ stands out as my absolutely favourite zone though, and Mirage Saloon is disappointing because of its short length. Act 1 as Sonic and Tails is a total throwaway, whilst Act 2 is simply too short. Short and sweet though, it has to be said. Now Act 1 as Knuckles is great; the reliance on gliding and climbing is unobtrusive and those abilities really come into their own unlike before. I don't know what I'd call my last favourite zone. I really enjoy all of them. The game is of consistently top quality, so any least favourite of mine would still be a good level.