Yeah, I have played through everything twice as well and made sure I did everything possible. I am to the point where I don't care anymore and I want to get rid of the game otherwise I will see it in my collection and it will stress me out.
I hate being a completionist sometimes... Especially with games like this where it is beyond your control whether or not you can actually complete when you have done everything required for the achievement. If only I could shut that part of my brain off that cared about completion percentage. Ah oh well.