By far, the most unluckiest of my deaths involve me peeking into a room and getting blasted by like, three manucbi. I never had a chance. Seriously, all the radar shooting in the world never have touched them; my best bet would have been blowing up the whole damn level.
Just had a Vile/Mancubi pack twice in a row while attempting Runner Gold (which is ridiculously harder than not-100%, lemme tell you). Unfortunately, while the first one was in a nice corner, the second was out in the open, and I had little time to react. Mancubi in an open space is definitely a crapshoot, especially when you're running. I'm really starting to hate that badge (this run and the run that gave me Trigun but killed me with a level 3 Rev, followed closely by the 200 or so runs of me dying on the first level and its insanity).
Demons are a lot harder now, too, just because of (what I assume is) a small HP boost. The fact the can hit you twice between your moves can REALLY take a chunk out of your health. Had a lot of demon deaths just because I thought they wouldn't hit twice.
Oh, and there was this one time against AoD where I ran out of berserk in the middle of fighting him. Absolutely pitiful, I hit him at least five times.