Click the green flag twice to start over. Use the arrow keys to move the blue character. Use the WASD keys to move the black character. The Black character is the only one who can stand on gray. Use the black character to help the blue character platform to the finish green area. It's supposed to be 2-player, but play it solo if you would like!
this just makes it so that the music isn't so loud as to break your ears, it also allows you to attach to the top of the platform, and it made a level more possible.