This is level 13 of The Crystal Gallery.
This level is quite hard, but it is not that intense. The Runner needs little explanation, just avoid making too many long jumps. You can try to use more small hops in the level, and this can reduce the possibility of missing a platform when you land, since the platforms are tightly packed.
The Child can do very long jumps, skipping past big chunks of the level. Consider to do a high jump, then keep floating until you land slowly on a platform. Repeat this process for a few times and you will beat this level in ease.
The Bunny should do a few short hops, and can then do a big long jump, again skipping much of this level. If you think you can't gain enough momentum by keep jumping in this level, try to beat the last level again and keep hopping during the transition between the previous level and current level. In this case, you won't have much difficulty to beat this level.