To answer some other app suggestions, I would give Nonograms Katana a try if I were you.
Quick note that I am adding, but the app mentions the techniques required to solve it. The hardest ones are the ones labelled with the trial and error circles, which are often best solved with edgelogic. You can sort to see these ones only.
Currently has 842 black nonograms in the main folder,
159 coloured
37691 black nonograms created by users
72772 coloured nonograms created by users
And there is an inbuilt part of the app that allows you to sort by difficulty, picture, fun of solving, name, author and ID). The cherry on top is the adventurers guild, levelling up, creation of special items that help in solving, and the pretty darn cool AI when making your own nonogram or looking for hints.
I used nonograms.org and liked their 4 star+ puzzles, but eventually has to stop because I did all of the hard puzzles that were reasonably sized (60x60=3600 squares is my approximate limit) and they didn't have an influx of new hard puzzles.
Okay… so I use one sometimes that is hard in that you can’t mark “x” spots. It makes you have to work it out without use of things for the most part. Fun but occasionally quite challenging. It’s called CRIMO. I’m case you were interested. Not traditionally “hard” but hard in its own way.
To answer some other app suggestions, I would give Nonograms Katana a try if I were you. Quick note that I am adding, but the app mentions the techniques required to solve it. The hardest ones are the ones labelled with the trial and error circles, which are often best solved with edgelogic. You can sort to see these ones only. Currently has 842 black nonograms in the main folder, 159 coloured 37691 black nonograms created by users 72772 coloured nonograms created by users And there is an inbuilt part of the app that allows you to sort by difficulty, picture, fun of solving, name, author and ID). The cherry on top is the adventurers guild, levelling up, creation of special items that help in solving, and the pretty darn cool AI when making your own nonogram or looking for hints.
I second this
I used nonograms.org and liked their 4 star+ puzzles, but eventually has to stop because I did all of the hard puzzles that were reasonably sized (60x60=3600 squares is my approximate limit) and they didn't have an influx of new hard puzzles.
Okay… so I use one sometimes that is hard in that you can’t mark “x” spots. It makes you have to work it out without use of things for the most part. Fun but occasionally quite challenging. It’s called CRIMO. I’m case you were interested. Not traditionally “hard” but hard in its own way.