After only 20 minutes in, it seems like at least half of its' problems are rooted in the Sonic Worlds engine. That's what it's running on right? The physics are that nasty Sonic Advance 3 flavor that just makes everything more dreadful - too much momentum when you don't need it (most any precarious jumping situation), and too little when you do (slopes, jumping over spikes directly in front of you, accelerating from a standstill). Thanks to that and some heinous old level design, Bridge zone is nothing short of painful.
I like where this remake's head is, I really like the stage art (Green Hill is a little flat, though) and I want to like where this game can go from here in future updates - certainly feasible since they have a complete game to work with now - but for starters, it deserves a better engine than it's got, Stealth's perhaps. Or a lot of ironing out bugs. Speaking of which, if you game over in Bridge, the game gets stuck and you have to hit F2 to get out...
And you nearly had my undying loyalty for making the default music low-weight MIDIs in consideration of slow connections. Thankyou thankyou thankyou thank you for that.
I have some other problems with the layouts and object placement but that i'll get to later.