Incredibly impressive work for a single person in 9 days.
I only played on normal mode, but it seemed like the optimal strategy was to dig out a semi-square centered on the entrance to the mines + try to avoid digging metals, and then spam build towers right by the camp. Once you figure that out there isn’t much else to optimize, so it seems like there’s some missing complexity (different types of towers, or some other source of complexity) – but obviously this is a jam game.