I've only played Mega Man 2, so...yeah.
Air-Man was easier than the song makes him sound.
Wood-Man's pretty easy too, as long as you bring Metal Blades.
Metal-Man the first time around, you may need an E-tank for, but they're still pretty easy.
Flash-Man? Don't make me laugh.
Quick-Man's lasers are all he has going for him; Time Stopper kills him at a 2 : 1 ratio in DIfficult mode.
Bubble-Man has a simple moveset; stay above him and you can mow him down.
Heat-Man can be tough...if you keep running into him like an idiot.
That leaves only one robot master.
Crash-Man. Mind-numbingly frustrating, the only one I can't kill with just a Mega Buster. He kills you in exactly seven hits, I counted!
Naturally, I'd incorporate the tower that the second half of the level is composed of, but the first half needs revamping. Perhaps the first half could be underground, with the generic arrow shooters attached to the walls for the moving platform part.