A neat and fun idea that seem slightly hampered by the controls. I think for as fast paced as the music is, and the chaotic and ridiculous nature of what's happening on screen, the dolphin turns way too slowly. And it seems like while you're surfing, there isn't much control over what direction you're rotating it. It almost felt like the dolphin was top heavy, and was making the surfboard spin downwards.
Those are my only two hang ups in an otherwise fun premise. Its fun to knock over surfers, and once you got some speed going on the surfboard it was really enjoyable. Nice work!