Zombie evolution

Yes, but once the player gets strong enough, priority one would be to kill any zombie that appears, hostile or not, to save time. So they wouldn’t be much of a credible late-game threat. The alternative would be to keep them invisible to the player and spawn them in with loud noises, which is basically identical to dynamic mode spawning.

I just think spicing up static mode shouldn’t be a matter of turning it into dynamic mode.