I am strongly opposed to zombies re-spawning in SP. In Mp its fine, but the thing that made this game so cool was going to an area killing a lot of zombies and then knowing the next time you came back if there were any more zombies they would have literally moved from another part of the map due to a large noise or meta game event. Now that is not the case as you have no way of knowing if they just spawned in or not. Another big appeal of this game for me at least was the prospect of wiping all the zombies out, I know this is next to impossible in SP but it was cool when you could cause a highly populate area of zombies to become empty and then have the terrifying moment when the meta game would move a large population of already spawned in zombies into you area. Another thing I was looking forward to was when NPC's are in the game, clearing an area of zombies and then seeing how the NPC's reacted to area's that now have a low zombie population and also the shift in dynamics the game would take at that point as it would become more about survival from man at the late stage of the game, which is what I think in really life it would eventually become. Zombies would still be a threat as the meta game would eventually move zombies from a populated area to you or alternatively you would unknowingly drag zombies to your area. All this is now not possible as of the new build due to zombies being able to re-spawn. I have been following/playing this game from pretty much the beginning and have always supported/loved every single idea you have all had, however not only is this the first of your idea's that I strongly dislike but is probably the idea that could literally in my opinion ruin one of the greatest things about this game (no enemies magically appearing in the world like every other game). This is of course all my own opinion and ultimately its your game and vision to do what ever it is you see fit. I however believe zombies in SP being able to re-spawn is not only a terrible idea but also goes against one of the things that makes this game so unique.