Gravity Slider is the 7th stage of Advanced in Super Monkey Ball 2 (26th in Super Monkey Ball Deluxe), the 7th stage of Volcanic Magma in Story Mode (11th in Super Monkey Ball Deluxe), and the 86th stage of Ultimate without continues (66th with continues).
The level is a long, downhill platform. It starts out very wide and gradually gets narrower. Until about 1/2 through the slider, ramps appear frequently on the sides, some of which have Banana Bunches. The area beyond the ramps is only open space. After 1/2 of the level passes, the ramps disappear, leaving a straight, downhill platform. The goal is at the end with a Banana Bunch behind it.
To get to the goal, simply hold forward until you reach the goal.
If you want to get more bananas, turn toward each ramp with a Banana Bunch. Then, while in the air, angle the control stick back towards the center of the slider. Although this is a good scoring opportunity, it can be difficult to stay on course, and it may be hard to center yourself back to reach the goal.