I game-overed AFTER defeating Death Bringer. The result is hilarious, in my opinion. Now, my question is: Would that run have counted, if it turned out to be a PB? Did I beat the game?

Yes you beat the game, and this doesn't affect the end time. This has happened to me a couple of times but only on the steam version. I think it can probably happen on all versions it's just not very common. Certainly made my laugh whenever it does though :)

awesome!