I think for the camera, it’s not a global rule, but walking up right next to a wall, most time you want to show some of the floor at the bottom of the tile you are on. And to not get a really wide perspective, moving the camera back a bit is part of the trick as far as I’ve understood it.
With the red planet maze, it might also be that the exit could be a little bit clearer. Since the cave is dark and you enter from a well lit room, it could make sense to make it bright even. I bet I passed by or was looking at it when trying to find my way out without realizing it.
A compass could be a middle ground, but I totally get if you don’t want to add that.
As for the runes, I’m not 100% sure what I did, but I only had 1 rune in the inventory when I reached it. I placed it in the middle slot, then I might have just walked away. Later when looting other stuff the UI popped up again and again. But it wasn’t there if I opened the inventory. Because I was wondering if I could trick the game to turn in the puzzle while standing next to the exit but the two ui wouldn’t be on screen at the same time.
Adding time as a secondary constraint on the eyes would be a great solution, I think.