This is level 4 of the A-Tunnel.
First of all, take one look at the picture. What do you notice? The rest of the level is like that. Normal tiles, crumbling tiles, normal, crumbling. So using the Child, you don't even have to move and you will instantly beat the level. If you don't have the Child, use the Runner.
If you are using the Runner, try to avoid the crumbling tiles. If one of them crumbles, the rest will crumble as well, increasing the difficulty of the level quickly.
As for the Pastafarian, try to walk on the light bridge most of the time. Avoid the crumbling tiles since she is most vulnerable to them, being able to stumble and get trapped by her own bridge. More risky, but more effective, you could dislodge the chain at the beginning, and the bridge will account for the missing tiles.