Party after midnight

You and all your friends have gathered for a spooky Halloween party. The pumpkins are carved, the coffins are emptied and the music is booming.
But all that spook and horror attracted your neighbours' attention, and they are not happy - to say the least!
Defend your party guests from the jealous attacks of your spectral neighbours! Hit the right buttons ... ehm notes and you will send them to oblivion with your angelic voice.
So what are you waiting for, the stage is yours!