I just recently beat Diablo and when I went to look at my achievements, all of my act 2 achievments were not there. I don't know how i could kill Diablo and not beat anything in Act 2 according to my achievements. I figure its just a glitch of some sort but i have A1, A3 and A4 beat but nothing from act 2 was completed. Little confusing.
I'm missing a bunch of achievements as well, but they're all over the place. Things like "reach level 10" or "acquire/level the blacksmith/jeweler" when I'm level 33 and have a level 5 smith and level 3 jeweler.