greate idea i was thinking about it as well but not in your way wich u suggest to increase even more dmg from zombies and their toughness. Cause whats its actualy changing to difficulty gameplay wise? basicaly nothing. u do same things as before just only now need to hit them more time wasting more "boring" hours of gameplay.
Instead i was thinking about something that can be added to zombies that would change our strotegy about how to even approach fight with them. For example increasing theyr running speed even farther so they now could run faster then the player. With that we no longer could fight endless amount of zombies in the open just running around them till we got our staminas back. Now its probably gonna be only 2-3 zombies max. And if u HAVE to fight them in open - then u SHOULD'v create at least some structures for u to play around. Even tho this one change already feel enaugh to change the game and fun to play around, i was still filling not satisfied but not invented some any new interesting ways or mechanics to add for zombies or create some new interesting zombies with new mechanics. idk. still thinking more ideas to this day till i create new topic about this

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