Don't worry, bughunting with a time limit of a week is a real challenge - and it's one of the few areas where having more contributors can actually make things more complicated in a project. Some things that may help to pin it down:
- As I said, I was clicking very rapidly while shooting, so my first instinct was "maybe I managed to create a timing issue with a check that should have prevented me from shooting?"
- I was playing in Firefox 125.0.1, maybe part of the engine doesn't work well with it? Don't know which browsers it was tested on
- For the situation of the screenshot, I deliberately waited a bit not killing (many) enemies, so maybe part of the check fails because it assumes the player is playing "normally", moving and shooting enemies?
Good luck on bug hunting! And, seriously, good work either way!