It was really fun. You are right with the enemy attack speed, at one point I can't take any ingots or leaves, not even in between spawns.
The healing I don't know for sure but try it out, when I had 20/3 or something crazy like that, I expected to get full health and I didn't, possible bug because is adding more than the max_health? should get a reimbursement of the leaves that hadn't been used?
Those are fine grained details tho, congrats on the game.