Actually, I've already beaten the game. Just need to get the rest of the achievements and all the treasures (I'm kind of wondering what area I could have possibly missed to not have Explorer yet, though [EDIT: Turns out it was the area with the developer fish]). Of course, I'll probably end up replaying he game soon since it's so good.
Anyway, I found the Sun Key, so assuming there's only two treasures in the temple, I found them both. And I also found the memory when I went through the temple the first time, so there's no chance of that being it. The sparkles still remain, though.
Just out of curiosity, is there a screenshot button or do screenshots have to be done via print screen and pasting? There's a screenshot folder, so I figured print screen would automatically dump screenshots there, but I had no such luck.