I've been thinking lately, that the ability to refund your items that you bought in the shop would be a good idea. This concept is simple, you get your green coins back, you lose said shop item. This is helpful, as you may have bought a shop item that you regret buying, for example, last human gets a saw, more often than not, the saw changeover results in you getting killed, so you may want to refund this buy. I can't see any downsides to this, as you're not like getting any extra green coins that you haven't had in the past. If you find any, feel free to post them.