Click the green flag and then click which song you would like to play :) The rainbow line in the black section is the sound detector, try saying something!
Just a little fun project to make, didn't take that long. I used cloning to make the sound detector, also you must click allow in when the adobe flash player thing pops up in order for the sound detector to work. All music is from previous games, which some you might recognize from other official games like Kirby.