Nothing -NO
Add Zombies Back -NO , go play dayz
Mutant Animals -NO, Animals drop ammo and shit ? doesnt make sense
Mutant Humans -NO, similar with zombies
Dinosaurs - NO, there r already another dino survival game coming out
Robots - Would be interesting but NO , doesnt match this type of game
too advanced
(unless you are going to add some "future weapons/buildings" )
Other Players - Yes but also need some npc for farming
Military - NO , Other players would become the "military" , no need dumb
npc shooting around
Giants/Mythical Creatures -Maybe add some Mythical creatures as "boss npc" to some
specified area (loch ness monster on lake ? lol ) but definitely not
the right npc to farm
Aliens - NO , Same as Robots
Tribe/Caveman -Yes , Put them to Guard Chests/treasure or Drop weapons make
more sense than others , they use spears, hatchet....... as close
combat weapon , bow &arrow (or handmade Guns) as long range
weapon , so you can not jump on a foundation and hit them to dead
with a rock , More challenging More FUN !!
If you want more fun and realistic environment , tribes definitely is your choice!
+1 exactly what i thought