Wow, Shawn. Just..Wow. I've never heard of you, and, tbh, I have a slow PC, but I closed all of my tabs and it runs just fine. Don't put down a game just because you can't play it.
I think there should be much less double notes, and much more quick single notes. Solo's need to be made near impossible, and a 'make your own song' part could be brilliant.
Stopped at 50138. Found a slight glitch that people might want to try. If you build a body tower up the left (probably the right too) side, then stand next to it, the evil clones will attack air, leaving you to simply shoot the clones coming from the right.
 "mutate the labrat"){kind=icon}
 "Guitar Geek"){kind=icon}
 "Pico Blast"){kind=icon}
 "Rage 3"){kind=icon}
 "Frantic"){kind=icon}
 "Towering Forever"){kind=icon}
 "Meat Boy"){kind=icon}
 "It's over 9000"){kind=icon}
 "Drop Dead"){kind=icon}
 "Spin The Black Circle"){kind=icon}
 "Click The Panda"){kind=icon}
 "Kongregate Forums"){kind=icon}
 "Straight Up Spinning"){kind=icon}
 "Fantastic Contraption"){kind=icon}
 "Body Ladder"){kind=icon}