Or, you could be less patronizing and tell me how any of what you said would have helped me in the example I gave. I knew exactly where each room is and had the path between them memorized. I examined the "puzzle" and thought I knew what I needed. In hindsight, of course, it makes sense I needed a second item but at the time it didn't occur to me.
I'm getting tired of seeing people intimate that if you have any trouble with the game you're a gamer that has been spoiled by today's games. I've been gaming almost since the advent of video games, it has nothing to do with anyone's cred as an old school gamer but rather that the game employs mechanics that are at odds with having fun with a game.
It would be a far better and more fun game if key items didn't take up inventory space. It doesn't add tension, unlike say the save system, it just adds frustration.