Bug Description:  Enemies still spawn and death animations/corpses appear, but they instantly die upon appearing. Bosses still spawn normally and can be fought, but otherwise no other combat is needed for the entire game.

Completing a sector or going to a new floor did not fix the problem
Problem persisted after starting a new run several times
Problem persisted after full game and system restart
Resetting in-game data fixed it

Steps to Reproduce:  I don't know exactly what caused the bug. However:

The problem started during the first game I played after downloading
Enemies spawned properly during the tutorial and only started dying instantly after I started my first run

Expected Behavior: Enemies spawn without dying and can be fought.

Attachments:  I have a compressed zip with the Diagnostic files and Player logs and tried to upload it following the report instructions, but it failed. I will keep it for a while if you want me to try to upload it again or want me to send it to you another way. I haven't included my system specs as it didn't seem necessary

I've also experienced the same bug on the same conditions you report.

Same thing happened to me. Deleting the save files fixed the issue.

This happened to me today on Xbox, Standard Edition.  Quitting the run, returning to the Saloon, then starting a new run did not fix the issue.  Force-closing the game and restarting the console seems to have fixed the issue, but now I've made progress to the next floor in a cheap manner, so I'm looking to reset progress.  I've been too excited for this game to progress via an unintentional hack.