Factorio Forums

If enemy_expansion.max_expansion_distance is decreased after a map has been generated many enemy expansion attempts will fail depending on map conditions.

Steps to reproduce:
-Download map (map starts with 255 spawners and expansion distance of 20)
-Count spawners /c count=game.forces["enemy"].get_entity_count x=count("biter-spawner")+count("spitter-spawner") game.print(x)
-Play map for 200000 ticks
-Count spawners (my result is 333)
-Reload same map
-Decrease expansion distance /c game.map_settings.enemy_expansion.max_expansion_distance = 2
-Play map for 200000 ticks
-Count spawners (my result is 255)

I think I'm going to categorize this as not a bug. While not configurable, enemies are required to expand some minimum distance from other bases to prevent areas from becoming overly dense.