This is level 3 of the G-Tunnel.
At the beginning of this level (which is in the picture), there are small platforms, but they are all connected and you can just use a jump from any character to get across them.
The second part is harder, and it includes crumbling tiles and ramps. There is one huge strip of crumbling tiles with ramps at the end, which you have to jump off in order to change gravity. The Child benefits more from the crumbling tiles, and the Skater benefits more from the ramps.
In the final part, there is a ramp you have to jump off to beat the level. Both the Skater and the Child can manage this, if you jump off it.