I suggest the flying sword and boomerang, as well as any other of these types of weapons be placed above layer 3, and the falling rocks as well.
It looks pretty bad when these go through something on a layer.
flying sword/boomerang
Oh. Oh my. I second this suggestion! It's very true. If you want to work around this, you can just place the trees on layer 4. Definitely. Layer 4 should be above the flying sword (V-force, I think it's called, but I'm not sure.) and the boomerang, with layer 3 underneath.
Great idea, Freedom. 😊