Apparently the Cursed Executioner, boss from the 13th day, is broken and spam infinitely.
So here's the workaround to avoid meeting this PC-crashing boss.

1- Play a custom game in peaceful mode and short days to pass the boss' night.
2- Leave the level once you reach the 14th day.
3- Start a custom game from 14th day to bypass the cursed boss.

Also you probably realized it but after a boss, the next day is always peaceful.

I'm sorry for the issue, I'll fix this awful boss as soon as possible.
You can expect an update around the 4th or June.


My deepest apologies for the worries.