Click on the World image to run it. Two "heroes" bounce to a soundtrack. You can change both the images used for the heroes and the audio soundtrack.
Exercise: Go to "My uploads" in the menu. Upload an image. Note the address of the image on Ancient Brain. "Clone and Edit" the World. Edit the code to point to your image. Click "Run" and your image appears in the World!
Top tip: Change the value of "speed" in the code and you can make it run super fast!