This puzzle is really interesting! I played some puzzles in mobile, and it works well in most cases. Vibrating when block edges are really good feature as it gives direct feedback to user.
However, in my phone when the puzzle size is bigger than 10x10, the outline dots of puzzle is out of screen, makes the puzzle unplayable.
Also, I found that system doesn't check the conditions about one single loop without branches, so the puzzle can be solved without making any loop and using only branches.
And when the puzzle newly generared, place any lines to see zeros change to green feels a little bit inconvenient for me.
Anyway, generated puzzle fits with their difficulty setting, and I like to play it with various difficulty and size settings. Thanks for sharing this joyful site!