I have been playing on Steam since its release, and converted/updated my walkthrough and flowcharts for the new version, including adding save points for the "Bundle of Choices" achievement, since there are a decent number of dialog options that only appear in certain circumstances. After all of that, and completing the game multiple times, my library shows 100%, the gallery is as complete as it can be without the patch, but I still have not been awarded the 100% completion achievement on Steam.
It's the only achievement I'm missing, and I would like to think I know the game well enough to confidently say I have seen and done everything, so it must be a glitch, but has anyone else experienced the same? Or anyone on the development side that could look at a save file and determine if I have in fact missed anything?