I'M PLAYING THAT LEVEL NOW!!!
I'm fighting that boss right now! literally! so cool. (yeah, i've got a Sega Mega Drive with the Sonic2 Game)
to all who want to know the key to destroying the final boss is to attack the giant robot's body (not legs or arms) while it is walking towards you (i prefer to jump to attack when the spiked fingers are as down as they will go), when the robot jumps up go to the exteme left of the screen, wait until the crosshairs lock then spin-dash to the otherside (i love waiting right before i get crushed, not recommended but it adds to the drama), when he shoots off his arms he fly's back up, do the same again and attack as he walks towards you. do this enought times and you win.
try to get all chaos emeralds as well, not only do you get to become Super Sonic in general gameplay, but the ending is changed as well. any Q's ask me, i completed everything about this game (i may not know all secret bits where there are items but i know quite a few)
back to the music, BRILLIANT REMIX!!, keep it up!