Love the in-depth review, thank you very much. :)
Puzzles were scrapped due to lack of time, but could definitely work with either the bag or just any items really, possibly under time pressure. The stealth sections were also considered, but of course, we didn't manage. I'm thinking simply having a radius around the player where they are heard, for starters. And some proper patrol routes.
The holstered gun "sharing" the bullet was at first done sort of purposefully to adhere more closely to the theme of one bullet, but we later agreed that it's kind of... a stinky pile of poo.
Did you hit the wall trying to exit level 1 into level 2? In that case it's just that currently you can step off the stairs during the fade to black and if you do, it doesn't transfer you to level 2.
If you hit the wall after demolishing the entirety of level 2, I first of all salute you, and second of all, yes, there should be a popup. It's even in the game. But some trigger got broken along with a bunch of other stuff because when the itch.io servers started having a panic attack, so did we. Well, maybe a little one. Anyway, here is your well deserved ending: