This was SO useful, thanks so much for the thoughtful response! I had been considering creating onboarding for first-time players and this confirmed how necessary that was, and helped me hone in on what to include.
I just uploaded a brand new build with a "How to Play" overlay when you first start the game (also accessible in the pause menu after it's dismissed). Hopefully this helps clear things up. Definitely let me know if there's anything that's still confusing!