Note: In this tunnel, since you can only use the Duplicator and the Child in this tunnel at first, so the character suggestion's choices will only be the Duplicator and the Child.
In this level, there are many small platforms, with many large gaps, probably due to the fact the tunnel is still forming. Try to gain as much altitude as possible by jumping on the ramps, then try to maintain the air. While you float down, assess the options before you hit the ground again. You need to think before you jump, so you can be sure that you can land on a safe spot and not miss the platforms.
If you can perform the trick reliably, jumping on the sides of tiles using the Child can help to gain height. Just make sure you can land after jumping very high.