Wall Decay Maintanance

[terse mantle]

When a wall randomly decays, instead of despawning, it shows cracks and is put on a ~3 min despawn timer. During this state, it can be repaired by a cement mixer. It despawns at the end of the timer.

[wise grove]

There is a hidden wall damage state that we could use for this. I do like visible cracks.

[crude lintel]

Please add this

Its really confusing for new players when turrets start randomly disappearing(ik because it took me a week at least to figure it out)