I'm playing on Windows!
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I figured out what the issue is. It says, "I have the key. I should try using it." Even if you don't have the key. Because it told me I already had a key, I didn't look for another puzzle. But once I found the book puzzle, it let me through. The message should probably say something like, "I need to find the key" instead, because otherwise people will stop looking for clues and try to figure out where their key they "should try using" is, haha.
Also very minor but since I'm at that part, there's a typo after you finish: "Looks like I have collected eveything."
Thanks again for your help! (And for the game, I'm having a lot of fun!)
