Swell is the 6th stage of Advanced in Super Monkey Ball 2 (25th in Super Monkey Ball Deluxe), World 2-6 of Story Mode in Super Monkey Ball 2 (World 2-10 in Super Monkey Ball Deluxe), and the 85th stage of Ultimate without continues (65th with continues).
This stage is a straight pathway that forms waves on the right and left sides. Bananas are along the middle of the pathway. The goal is at the end of the pathway.
There is only a Blue Goal in this level. Just head straight, and try to go over the hills and not be on the valley parts of the path. Do not go too fast as you will bounce from going too fast and go over the goal.