This level starts out as a much intact solid platform, but as the name of the level suggests, the farther into the level you progress, the less intact the platform is (perhaps its falling apart). One easy route through the level is to go to the left side of the level after the first hole in the ground, jumping carefully across the platforms, then doing a long jump to after the final L shaped platform to a small block to the right, then jumping the final 2 jumps on small platforms carefully.
This bonus requires you to stick to the right side of the level, jumping on the biggest platforms you can find, before jumping across to the bonus, and finally doing the last few jumps on small platforms. It will help if you only hit the edge of the bonus, as it is in a place where jumping normally will make you fall in a hole. Midair maneuvers are required.