FOR PLAYING: Click to go up. The arrows are speed, (one meaning +1 speed, backwards one means -1 speed etc..) And the curves are size, (one meaning +1 size, backwards one meaning -1 size etc.) FOR EDITING: Only edit the costume on menu for your song and length (the number of the end scene -1.) And the costumes in the level sprite, the assets are in the level sprite, as well as what they do. Oh! And (if you want) you can go into the menu sprite's code and change the music, you'll have to put in the different song yourself. Sorry!
