Oh gawd. I Just Wanna Burn, Tired Old Man, Presumed Dead and Switch vs Evil-Dog Round 3 are all easy compared to Guitar vs. Piano. Good thing I at least managed to get bronze.
YES! Finally got the hard badge, here's how I did it:
Put the motion on Wave and pattern on Straight. Try to collect as much shapes as you can, avoiding every red shape and trying to get every yellow shape. The badge gets so much easier if you get a Yellow madness or two (or many purple powers, like me).
thank you!