Totally agree on finding the last enemy, I also ran into this quite often in play-tests after I had submitted. In the future, I'd likely add a very obvious outline shader of some sort on enemies if they are the last 2-3 alive and none have taken damage for like 5 or so seconds.
As for the pit, I mentioned this in the reply above you, but the idea is for you to use the shotgun as a launcher out of it! I didn't get to include a tutorial unfortunately, but the shotgun will add velocity in the opposite direction of where you're aiming when you shoot, so you can use it while already having upwards velocity from jumping, and you'll have a ton of velocity to get out. There's also a few other movement techs that make it a bit easier, such as slide jumping will give you a bit greater vertical velocity which will help a lot with jumping out. Again, that's the problem with not having a proper tutorial ('tis my first game jam, so I did not realize the importance of it, but I honestly really should have!), but you live and you learn. Thanks so much for playing, I really appreciate your feedback!