I really enjoy facing various types of enemies. Thank you for updating this version to have zombies and biters on the same side. In the future, would you consider making zombies more distinct from biters? For example:

Smaller collision volume, allowing them to group more densely like in They Are Billions.
Melee zombies, though slow-moving, can grab players (reducing movement speed by 100%). There could also be a few zombies that move very quickly.
Ranged attacks could resemble vomiting: shorter range, but with continuous acid spraying like a flamethrower.
Or, similar to Left 4 Dead 2, there could be a low chance of spawning various Special Infected.

They should have a smaller collision box, but maybe that isnt working as expected. They definitely group close in the original mod.
But yeah that is something I would like to do when I get more time, I still need to revisit the graphics and fix the masks