The concept is pretty great. I really like the surrealness of it all.
I'd like to see more tree dialogue, you have to spend some time waiting by trees so it'd be nice to have new things to read. And the blue things could be a bit more responsive to apples.
It's great how you linked everything to giving shade, the orbs, turbines and even the checkpoints. Amazing job.
Also, I've been tempted to switch to Unreal, how is it?