This is the sixth level of the main tunnel. There are quite a number of crumbling tiles in the level, and they can be a threat if not handled carefully.
There are quite a number of crumbling tiles in the level, and most of them connect to each other. If you step on one of the crumbling tiles, a pile of crumbling tiles nearby will also crumble, like a "domino effect". These can prove to be deadly.
You should try to avoid areas with many crumbling tiles. Try to jump as few times as possible. This can prevent you from accidentally stepping on a crumbling tile.
Tips: If there is only a small hole in front of you, you don't have to jump. The momentum created by the Runner can let him go past the small hole without problem. If the hole is larger, you will have to jump.