It's like Myst, Portal and geocaching combined!

Nice, they made a viewport transition into the actual geometry - i bet it was simpler to pull off in code than one might guess. I do love these sorts of puzzle games, but they always manage to be such a powerful concept that the puzzles themselves are sort of easy. This is obviously more of a walking simulator, but the puzzle game where you have to resize objects based on perspective is a good example of what I'm referring to. Forgot the name.