The start of the final chapter when you are introduced to the final monster type. I was running low (read: only had 15 Dentist rounds) on ammo at the end of the previous chapter, and the game has locked me into the first fight sequence with exactly 7 shotgun rounds (from two barrels) and the the 15 dentist rounds I had going into the fight.

To make matters worse: if the enemy gets too close, you enter into one of the worst (if not the very worst) quick time events I've ever seen in a game. Twenty tries and I'm giving up, I just don't have the kind of ammo I need to kill it. Doesn't help that the shotgun (whatever it's called) is the one weapon I hardly ever used, so I haven't put any points into it at all.

Granted, this won't happen to a ton of people, but the conditions were just perfect to turn this into a case of incredibly bad (if not almost impossible) checkpointing. It's a shame, too, because I was really having fun with it up to that point.

Oh well, back to the rental store it goes.

I never once found myself in a situation where I was that short on ammo. Hell, in bigger situations you even find crates that will respawn and give you as much ammo as you need, provided you survive long enough.
 
Sounds like you're just bad at the game.

Look around.  Ammo boxes respawn ammo after a short time, or maybe that was just boss fights.

@Zippedbinders: I was playing on Hard and used up all my ammo fighting the last sister. This was actually one of the few places I died, besides the terrible big-boner section. Sounds like you're just an ass on a message board.

@John1912: Yeah, a lot of times there are. Surprisingly, there aren't any at this checkpoint, which I found pretty odd. Maybe those boxes are just at the bosses and "min-bosses", but seems like fighting this new enemy for the first time in a room one on one would satisfy those requirements.

@marioncobretti: Read something to that effect before I gave up, but unfortunately had zero handgun ammo. I tried shooting off a bomb and using the shotgun to detonate it, but that didn't work so well. That gun is the worst (or at least it is when it hasn't been upgraded any)! May give this one another go some time in the future, but just decided last night to give up and take it back a few hours early.

Hm, did this part on hard yesterday as well. Granted, it's annoying when you have to start the entire encounter again when the big demons get you, but it's doable. 
 Btw, I'm pretty certain there are at least some ammo boxes at this checkpoint (around the courtyard) and I'm pretty sure they even respawn. Keep running around if needed. The game makes sure you don't run out of ammo I think.
 
The last demon type goes down with two sticky bombs to the weak spots, even on hard. So all you really need is some boner ammo. Was surprised at how fast they went down yesterday.  It is not a good idea to NOT upgrade a weapon in this game.  On hard I maxed out the damage of the 3 guns first, then went to health, then some capacity and reload. The damage output of the maxed shotgun is pretty insane and even single shots are really powerful.
 
btw I'm really starting to think Suda put that broken qte in on purpose :p