I've encountered many errors with my DRPG, but I fixed them all. PM me what you need fixed and I could tell you how.
Oh and there are helmets, but there is no crafting for them in the leaked version. Monsters spawn after level 10 by the way, not 15. Zombie mod has nothing to do with this though, because DRPG Mod creates a default minigame on its own, and you cannot manage the options.