The last puzzle you'll probably solve is moving the boulder from the cave. During the game, you may see eyes peaking out over the top. The logical assumption would be we got to see what was in the cave. The joke is on us this time. After all the puzzles are solved, there is no big reveal behind the cave mystery. The game continues on as if the puzzles weren't solved. There is no big ending. The only thing you'll get from solving all the puzzles is the satisfaction you did solve them.