Try to get your optional stuff on one playthrough. the levels are long enough you don't want to have to try for them again. Not sure if you can quit after completing one and keep the quest, never wanted to try. I have found most of the scrolls and challenge rooms, but not all..those are the only achieves I have left for 100%, perhaps we should start listing where they all are. Unfortunately, that stuff didn't reset for my NG+ so I could only mention the ones I havent found yet as I do find them. Great game, plenty of levels, I really enjoy sneaking around and whatnot, creates a really fun challenge! BOught this the second it dropped, hope you guys continue developing! Oddly enough the most difficult achievement for me was killing 2 enemies with 1 chandelier. Won't post any spoilers, but also loved the ending :)PS on a sad note, I didn't get the avatar unlocks for being the regular game...I'm hoping after NG+ is done it will unlock them all? I'll find out here in a few hours and post when done.