Nah, glitches are pretty normal, they happen and most of the games have some of them, even if some users didn't have such experience.
DMC 4 had bad glitches like the one during Bloody Palace, when a Faust simply disappeared. He only came back when the countdown was reaching zero, lol. It's on youtube.
There are others too. Some people are really blowing DmC out of proportion, treating it as if it was the only game to have glitches, and flaws when that's wrong.
That being said, these are pretty funny glitches for DmC and some of them are useful. XD