Press up arrow to jump, left arrow to scroll/move left, right arrow to scroll/move right, and space while touching boat to go. Click him to change color. Click the green flag 4 or 5 times. Avoid lava. Up arrow to jump, press f and after that up arrow will make you fly. You are the square. Turbo mode is RECOMMENDED (Shift+click on green flag)!!
Thanks to Scratch 1.4 for the example project with similar scripts for guidance. Press 1 to change lava color by 10. Press 2 to change lava brightness by 10 and 3 to change brightness by -10. Press FLAG AND WAIT UNTIL THE SQUARE IS TOUCHING THE BLACK FLOOR BEFORE YOU PRESS ANY BUTTONS.