Gray is just the terrain. Red is lava. Don't touch it! Yellow is trampolines (very bouncy) Green is the end. Try to get there. You can change the level by pressing the Arrow keys or by using the slider. Press Space to show / hide advanced settings (use the sliders). Press Enter or click anywhere to start the race. Get your friends, siblings or whoever on your side. Which marble will get at the end first? It's always randomized. Place your bets!