This is Level 4 of Run 1.
This level combines movement and gravity switches. The big holes might be terrifying for beginners, but this level is still easy, although it may be harder than the first three levels, since there are more holes than the first level. If you stay on the original side of the tunnel, there will be a tricky jump for beginners at the end. Switching to the right near the beginning is the best strategy, as the path will be much easier as there will be smaller holes in the ground.