Yes,
Devil May Cry is one of my favorite game franchises of all time. This can be taken as bashing, but honestly, I'm only making this cuz DPAlucard told me to. ^.^ And may as well point them out.
It was originally supposed to be off the top of my head, but I winded up coming up with, like, 1 point, so I researched some of the rest again (I even included non-canon points and non-released game points, just for the hell of it):
Considering this entire thing contains spoilers...
-DMC1 clearly states that Dante lost his mother and brother to evil 20 years ago. But DMC3 states that Vergil (Dante's bro, for those who don't know) was lost to evil about 2-3 years before DMC1 (I'm not quite clear how long before DMC1 is before 3, its within a 5 year span is all I know).
-DMC4's novel states that Nero is Vergil's son, and that Nero was conceived sometime shortly before the events of DMC3. But using simple math, Vergil would be around the age of 11 when that happened. So either he hit puberty real fast or this is indeed another screwup. (for source, find someone who has a copy of the novel. I don't have it anymore)
-DMC1's novel states that he and Vergil fought before the events of DMC1. This cannot be possible, due to the fact that Vergil was currently in the demonic realm under Mundus's influence. (However, this novel is no longer canon)
-It shows clearly that Eva (Dante's mother) had blonde hair and that Sparda had silver hair. So where did Dante get the black hair in DmC? (Note that this pertains to a game that is unreleased. Fan speculation also says that he dyed his hair because he was "ashamed of his demon side")
-As minor as this is, it should be pointed out. During Dante and Vergil's first battle in DMC3, Dante was not wearing his amulet, nor did he put it on during the fight. However, after the fight, Vergil was shown tearing it off from around Dante's neck.
This is all I typed out from using what I thought off the top of my head and using iMDb. There are more, but I can't really think of everything at the moment. Excuse what I said before, I didn't mean
more screwups than
Castlevania, I commonly exaggerate things. Sorry if that screwed this whole thing up. ^.^
NOTE: I only used memory and iMDb. There are much more out there.
If you have any others to share, feel free to post it. I'll update as I remember/find more.