This is level 5 of the U-Tunnel.
In this level, large amounts of crumbling tiles are present, and worst of all, many of them are inter-connected, which means if you crumble one of them, it will cause mayhem and large parts of the platforms will crumble.
Child is a great character for this level, as he can walks on the crumbling tiles without making them crumble, unless he jumps on them. So if you use him, try to walk onto the end of the long platform, and jump on it once you reach the edge, and land on another one. Walk along it and jump when you reach the end of the path. Repeat for a few times and you can beat the level.
As for the Bunny, you can try to run on the crumbling tiles before they crumble completely. When they are about to crumble completely, use a high jump to leap out of the danger and reach for the other paths.
The Runner is also great, but you need some skills in order to jump on the platforms. This can be quite challenging.