Hi, thanks for playing and for your feedback :)
As to the problems you mentioned I fixed the HUD not being there (my stupid mistake that for some reason didn't show up while testing), but I was unable to replicate the issue with platforms during boss fight, I tested it a few times again and they always respawned when I loaded the save. As to the closing and reloading of the game, the UI dissapering also meant no death screen, sorry about that, it's all in place now.
End screen looks like this:
so I can't say you missed out on much :D
All in all, I'm really glad you liked it, I played Painkiller a lot in my childhood and the new Doom games are among my favorites from recent years, so I'm glad a I was able to capture a little bit of that feel :)
P.S. I applaud you for playing to the End regardless of the UI bug, I would have probably gave up :D