EDIT — I SPOKE TOO SOON. This patch introduced a crash that I have now rolled back. Please download the rollback patch ASAP
Achievement for filling out the gallery should be fixed. To trigger it assuming your gallery is already complete, just go through the motions of unlocking any one gallery item (so finish a chapter?) Let me know if there are still issues with that one.
Added a check at the beginning of the game to see if players have previously earned the "Our Song" achievement. If they have, automatically unlocks the gallery. Should ease some confusion on how to access it for returning players.
I'm still trying to map out a one-time check to partially sync gallery progress to what achievements a player has already mapped out to see how viable/helpful it would be. Since so many items in the gallery aren't tied to achievements, and achievements tend to be less granular than gallery items, it's unclear how much a partial solution like this would actually save time for players, and I'm wary of the risks making any mistakes in its implementation would introduce.
So... still leaning towards no for trying that, but wanted to give you all an update and to let you know that I am earnestly looking into it.
Cheers, and thanks so much for a fantastic Pristine Cut launch!