what was the hardest part of the puzzle validation logic detecting unique solutions or handling edge cases in user input?

Love it. Inspiring me to upgrade my puzzle game site.

The homepage is a little overwhelming, other than that cool site

Are you blocking Tor?

I hate that it immediately flags your errors. First, because it doesn't forgive the casual finger slipping or forgetting if you are in pen or pencil mode. And then because it partially gives away the solution.

I also hate ads in games, ... and as another serious restriction I only play on thumb slide games (think 2048) that just make me think enough (i want to relax) so I and Fable 5 developed https://squishy.franzai.com/ (Design is Opus 4.8, iOS Frame also Opus 4.8 - as Fable was gone by then).

Now waiting already for a week for Apple greenlighting my iOS update for the level builder...

Or you could use https://krazydad.com/ which has been around for decades, contains interesting puzzles many of which are types the author invented, and isn't AI slop.

eventually hosting costs money, so ads will be needed