Walls

[JaminRoyale]

Stone Bricks = Stone Walls
Concrete = Concrete Walls
Reinforced Concrete = Reinforced Concrete Walls

Stone walls are designed for small - Medium enemies. Concrete for Medium-Large. And reinforced for Large-Behemoths.

There really needs to some better late defensive walls in base game Factorio

[SyncViews]

Also consider that for mid to late game the player should have construction bots, with their ability to repair and rapidly replace any walls, and you can have multiple layers of walls backed up by many turrets.

Behemoths already struggle a lot against such stone wall defences (even assuming zero space tech turret upgrades).

If Factorio did add additional wall types, I think stone walls should be notably weaker (small biters really struggle to break them anyway) with top tier not being too much of an improvement over now.