The excellent thing about Blue Prince is that it isn't afraid to keep giving you more clues. I've seen people go "Bridge. Bride. I see what's happening - I will write these down" on day one. But I've also seen people walk into Study, look at the chart and go "Huh. I wonder what that's about" and walk out without any flicker of understanding. Those latter people will, hopefully, one day read the Letter in Herbert's private chest freezer, and maybe that's enough.
The Gallery puzzle isn't actually an exception to that, but it's very close. There is one small clue, and two bigger one, and then it's you versus the artist. The small clue is in a document you've never read because you need all those keys†. That document is just another set of clues, sorry, you don't even get another credits rolls. There is only one Credits Roll in the whole game and it's for reaching 46 the first time on a save, even though that's nowhere near all of the game. There's a deliberate fake out, later, but no other actual credit rolls and no explicit end, just the game starts to point out that you can just stop playing at first in subtle ways but gradually quite blatantly. It is just a game, go do something else.
† Technically you could just guess an answer, but this is after all a puzzle game so where's the fun in that?
