Theoretically, if you build 5 hamlets and a waterwheel you have infinite prosperity. I haven’t found a map you can do that with, yet, because not building a citadel or mill makes the game basically impossible, but if I find mending scrolls at the right time it may be possible, especially if there’s some kind of special space that gives XP or health or max health or something. Even as is, 4 hamlets and a waterwheel yield ludicrous prosperity so whatever upgrades there are between rounds if they are prosperity-based will make infinite prosperity on hold two possible if not easy.
upgrades in between maps will be bought with gold. Prosperity is basically a high-score and it'll carry through maps for a full run. So ultimately, generating prosperity will be an optimization/minmaxxing issue for people wanting high scores.
Will post some updates soon, as I've currently gotten good UI/UX feedback and working on revamping and improving the early experience a bit (and adding a bit of a playable tutorial).
Thanks a lot for playing!