Get over the tall hump to the right and jump to the first one-way platform. Run off it to the left, and aim yourself to land on the fourth platform. Now fall on the curved hump and run all the way across the small hills to get the switch. Run back the the right, and walljump between the far right wall and the curved hump that you fell onto earlier. Jump up the platforms one by one, then jump in the ditch and get to the exit.