AI UPDATE

[egor9092]

Now in game if you met a zombie,  you can put block, stay on block, jump and put block down under yourself, if you upgrade this block you will become almost invulnerable to ordinary zombies.they just don't attack the bottom block with 100 hp, but hit the top upgraded block. Ai needs to be updated so that they hit the weakest block in the structure to get to the player, player can't repair 1 block.

Now you can see abuse like this 

https://clips.twitch.tv/AssiduousHumbleChipmunkVoHiYo-x841JwIsQ_BJ1NTw

 

Sorry for my English I'm use translation. 

[Misamor]

What you're asking is way more complicated to fix than how much you seem to think it is.