Yeah unfortunately the boss bugged out when I exported the game for the last time -- I had it working on my first export, but I realized I needed to fix something (completely unrelated thing), and when I re-exported it, the bosses' animations weren't set correctly and it did not shoot projectiles for 2/3 of its attack animations. As for falling into the pit, it's a bit of a byproduct of not having time to include a tutorial, but it's meant for you to use the shotgun to propel yourself upwards! Shotgun shots will apply a backwards force to you additive-ly to your current velocity, so jumping and shooting straight down will send you straight up out of the pit!
Definitely a lot of stuff I wish I could have included/fixed (#1 would have been a tutorial, big miss on that, but I know for next game jam!), but I definitely want to re-visit this game in the future as a longer project. Thanks so much for playing and for your feedback!