Downhill Hard is the 11th Expert floor in Monkey Ball and Super Monkey Ball, and the 9th Expert stage in Super Monkey Ball Deluxe. It also appears as the 119th Ultimate stage with continues, and the 159th without.
It is a much harder version of Downhill. It is much steeper, and it has bumpers instead of walls.
Take this as slowly as you can without running out of time.