This is level 6 of the New Tunnel.
In this level, we recommend using the Child since he can float to far places, such as a platform that is far away. But using him may be a little bit risky, since the platforms are only wide one tile, making landing a bit tricky. Fortunately, there are quite a number of walls in this level, so you can decide to land on a wall if you are urgent of landing.
Using the Duplicator can be great too. You can try to keep jumping off duplicates in the air, if the spawning frequency of the duplicates is high. Then you will soon keep jumping in midair till the end of this level.