I know, sorry about that!
I actually tried using them about 3/4 through the development, but found some problems. If I recall correctly, the trees were overlapping the player even when he was below them (the player global_position.y was greater than the tree global_position.y), and also the background was giving a lot of trouble (I used a sprite2d node for the BG, and somehow it ended up being on top of everything, and changing its Z value ended giving me odd results, like the player getting invisible after a certain y).
I don't think this is a Godot glitch, but rather a result of my messy project hahaha surely it can be fixed, I just need to get the courage to do so. Anyway, thanks a lot for playing and giving feedback!