Personally the only problem i had with Episode 1 was the Bosses. They were soooo meh at best. I only liked Lost Labyrinth's Boss Battle 2nd phase and Mad Gear's Chasing phase Boss Battle.
Even then the music behind it was making it sound so out of place. =/(I don't like circus like sounds etc. but i liked the majority of Episode 1 music)
In any case Episode 2 looks to step it up with Metal Sonic of course:
Nothing to say here. Metal Sonic = Pure Win
And with Egg Serpentleaf:
Which in my opinion looks really good, unique and grand like it supposed to be. Which makes you think what are the other bosses like?
So yeah...what you think we're gonna see in White Park, Oil Desert, Sky Fortress and Final Zone?(I guess)
And of course the Music behind those bosses. For me Boss music play a VERY important role. It needs to give you that vibe of being on edge(well good players not so much ) that you're up against your arch enemy and pump you up to go beat the Boss!
Like this one for example(It's one of my favorites):
Ep 1 Boss music just left you like going up against a clown(Well Eggman is not that off) xD but that's besides the point.