The twist has to do with explaining the origin of the artefacts, exactly like the last sentence in the description of the secondary theme 'old gold'. Whichever way you can make friends come to your home is a good way ;) (don't do this at home)
yes some parts of the game like walking were tuned for the possibility of buying upgrades so they feel very slow and repetitive without that but I'm glad you played it until the end ! (oops I messed up my layers when drawing those 3 tiles and they ended up on the buildings layer)