Hello there, thank-you for catching so many of the bugs and sorry there were so many present!
The pit crash is something that I've noticed too in testing, it was caused by enemies not spawning with a weapon (because of the new item system) so that should be sorted in the next update.
2 and 4 should be simple fixes, but 3 is a bit concerning.
Your point regarding the recruiting softlock is really important. I considered making the player's starting club a special weapon that leaves them with 1HP when it would normally kill an enemy (except if the enemy already has 1HP, then it will kill them) but figured that would get annoying when you're just grinding. Now I've got an equipment system implemented I think I'll add an accessory that gives the wearer an action with that same ability.
Yeah, the building system is a little janky and perhaps a bit too expensive too. I'm considering having buildings only require one stone for upkeep, and following your advice I might have the placement mode highlight potential deleted objects in red.