Hi there mate. Thanks for the 2.1 update. With the new api, all enemy units can build specific entities when expanding, so biter can build their own native spawners. So for each unit prototype, it would be great if you could change buildable_entities = {"biter-zombie-spawner","spitter-zombie-spawner"}, or more specific, each spitter zombie have buildable_entities = {"spitter-zombie-spawner"} and biters buildable_entities = {"biter-zombie-spawner"}

Hey!
Appreciate you letting me know. I basically updated the version and sent it lol
I believe I've updated as you've mentioned, I'll test it later and send out the update
Cheers

Completely forgot about this. Have added buildable_entities for both zombies that spawn their own spawner type.
Game launches without crash so I'm guessing its working.

thank you =)