You need a challenge, and you look on the forums, and you try some challenges out, but it isn't challenging. How bout this? Seriously doubt you can finish this campaign, and while I have never tested this mod yet, it should be hard. I disabled the workshop so you can't build any combo weapons. I decreased the durability drastically so yea, you better stock up on weapons fast. Zombies are given double health and their attack damage is tripled.