This is Level 9 of Run 1.
The level starts out easy, but gets harder as more holes appear in the tunnel towards the end. You can in fact beat this level without having to switch gravity, but it requires more skill and precision for more accurate jumps. The best way to beat this level without going through all of the hassle is to switch to the right once or twice near the beginning. This will give you an easier level to work with as the platforms are easier to jump to and are more frequent.