Thanks for your comment.
I want it to be difficult to encourage multiple sessions and quick thinking/analysis, so this is a design aspect I will decide to stand on.
Can you elaborate more on the bug? I've play tested it multiple times and the timer never just ends and that bug carries over to another puzzle. I just tried it now on my computer and a low-end laptop and completed the game with no bugs whatsoever. But you are the second to mention this so I'd like to nip it if possible but I have no clue what the issue might be. Since the event sequencing is all correct. So I have a few questions about it.
Were you on MAC?
Did anything else happen when the timer hit 0?
If you tried to start over from the beginning, did the bug persist?