Great game! I liked this one a lot. It's very clean and well thought out. The mechanics were simple. That's nice for a puzzle game. The point is to think about the logic, not how well you can figure the buttons out.
The only things I would really change are:
When a clue is completed, move it to the end. This keeps active clues condensed. Then players don't have to scroll through pages to find those last applicable clues.
Add some harder difficulties. People who seek out puzzle games like tougher ones. There are casual puzzlers (like myself), and people who just don't understand puzzles and think they do, so the easier levels are good for a much broader player base.
Have a random generation tab with difficulties. They would be named after the difficulty tabs and generate with that rule set. That would allow players to continue after completing the levels.
These aren't necessary, obviously. Your game already has a very high rating. I would just like to see more of it. :)
Good luck!
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