I was constantly losing buildings. I must have rebuilt my mills a dozen times. I never used more than a single of each military/support building. I didn't bother with walls until day eight or nine and purchased maybe three upgrades. I know I wasted a lot of time, and kinda put off taking down the cemeteries.
I finished the game on day 13, 30 souls under my command, and having only harvested a very tiny portion of the map. I dunno what your intended playtime was, but I feel I just kinda derped around and accidentally happened upon and beat the final level. The shades stealing your guys was neat, but this ended up being far less dangerous than something that could actually deal damage.