Nice! My wife and I just played through all the puzzles and really enjoyed it. A few comments:

1. The github repo is private. Otherwise I’d file issues there.
2. The ‘023: monster’ puzzle doesn’t complete for me. I have the right answer (I even checked the json) but the lock won’t open. Looks like the problem is that the inputs are `type=”number”`, but one of the answers is non-numeric.
3. How are difficulties computed? I tended to take longer on ‘medium’ puzzles with lots of bull/cow questions, whereas high-rated puzzles such as ‘insanity’ (66.6) were quick to solve because the arithmetic rules are easier for me to keep track of.
4. You should add emojis to your rules 🐂🐄. The text is a bit too verbose to easily grok.
5. I didn’t come across any rules like ‘one bull and one cow’. Is that deliberate?