Found this game a few days ago and I'm really liking it!
I did have a balance idea, if you're interested. I find that the Leftovers item is pretty underwhelming, at least at the point of progression I'm at, since it doesn't appear to scale at all with your HP stat. I think having it scale to restore a small percentage of your total HP instead of a flat 0.2HP/s (or 1HP/s for the + version) would both make it a more viable pick and incentivize increasing the HP stat more at the same time.