you can try recording video of whole process where you show what's inside of your .bat files and what files are created and what files you are playing back. That might help

0:09 : NOMO.BAT file 0:30 : I rec the run 1:14 : The Playback file 1:25 : The WTF moment hahaha

Damn... I have absolutely no idea what's going on there. Can you grab the older 5.9.2 version and test there?

I'm just gonna add this here, I record my demos with Crispy Doom and I had similar issues when messing around with nomo. My solution was playing the demos back through PrBoom+, so maybe give that a try?

I can try ; issue is that if I submit to Doom World, they'll refuse my runs

I don't think they would, as long as the demo checks out with them then there should be no issues. If you'd like to test using a different source port out, send me a demo recorded with -nomonsters, and I can try running it under PrBoom, otherwise as a less than knowledgable person I am stumped.

edit: I played back your original demo called 'e1nomo0450.lmp' using these parameters 'glboom-plus.exe -playdemo e1nomo0450.lmp -nomonsters', and it works. I have no clue if this is verifiable if the mods have to look directly at the demo file, a straight video rip is definitely doable with a command like this though.

This is extremely odd indeed. You shouldn't be specifying -nomonsters in playback file it should just grab the settings that demo is in and that should do the trick. You can try creating a thread on doomworld, describing your situation and adding that video there (just name it appropriatly, smth like "Issues with nomo playback on crispy-doom"). Or go to doom discord and ask there, maybe someone knows what's up.

@pretty_average: That's interesting! I'll create a topic on DW and also pointed your discovery!

Thank's all for your precious time :)