There was a bug that picked tile different where worm actually attacked for attack ticks evaluation. Just released an update, was testing this for 2 hours and, while there are still inconsistencies, they are much more rare now.
Currently tiles affect 3 things:
1) Likelyhood of worm attacking current chunk, strong tiles encourage them more to continue moving towards most polluted areas.
2) Number of attacks from underground. By default, worms have 6,12 and 18 attacks (Big, Behemoth, Collossal Worms respectively). Bricks reduce number of attacks by fifth, concrete by quater and reinforced concrete by third.
3) Delay between attacks. Default at 1 second, bricks and concrete extend that to 2 seconds, reinforced concrete to 3 seconds.
Also added targeting preference for walls, so if you build enough of them in a chunk, they may attack inside that chunk, depending on surrounding pollution. To make sure worms attack walls, you can tweak a new mod setting "Worm pollution weight", lower value means they are more likely to attack structures in current chunk than moving to higher pollution area.
I'm finally done with studies, so starting tommorow I will start a solid playtest on a fresh map until end-game.
