Pretty much all of them, to be honest. I think VN anime adaptations just don't work very well, although I can appreciate the animation.
I've watched the Code Realize, Amnesia, BroCon, DiaLovers and Nil Admirari anime adaptations, and I have my gripes with all of them. Otoge just isn't as linear as it appears, and I think it reflects in those adaptations :(
There's also the fact that those adaptations are more of a marketing move than actual faithful work, which sours my feelings on them ;b