jQuery(function(){
  jQuery('.screen')
    .sprite_layer({num_sprites: 5, xspeed: -10})
    .sprite_layer({num_sprites: 5, xspeed: -20})
    .sprite_layer({num_sprites: 2, xspeed: -30})
    .sprite_layer({num_sprites: 1, xspeed: -40, sprite_class:'turtle'})
    .sprite_layer({num_sprites: 1, xspeed: -75, sprite_class:'bullet'})
    .sprite_layer({
        num_sprites: 1, 
        xspeed: 75, 
        yspeed: -100, 
        sprite_class:'mario-raccoon'
    });
});