Alright I'll consider this beating the game, I don't think I can die anymore. It seems the longer you play the fewer the enemies spawn. So if you play long enough there are barely any regular mob spawns. See video. It might be because some of them spawn out of bounds and get stuck, I did see some stand around outside the walls. Often games like this will teleport enemies near you if you get too far away from them.
When I stopped playing:
Few spawns: