I just got a new phone, and realized that the only game I occasionally play, MathDoku, won't run anymore!
This was unacceptable, so I wrote my own: https://magnusm.uber.space/mathdoku/
Github: https://github.com/magnusmanske/mathdoku (GPL, feel free to run it on your own server if you prefer)
This is a "progressive webapp", you can play it in the browser, or install it like a "proper" app on your mobile (Chrome/Android trhee-button-menu, "Install app"; other borwsers/platforms, please let me know!). It will keep your game stored even during reboots.
Issues and merge requests welcome!
This is very cool! Coming from a beginner, it might make the first few games easier if you added an extra setting that would start the puzzle with one or two numbers already filled in (like a typical sudoku), as that gives a natural starting point. Obviously, it may not be needed if you mainly develop this for yourself :)
I believe in the Puzzle I attempted, the solution was not unique: at the end, two numbers could be placed interchangeably (in my case, I could switch around all "1"s and "4"s and end up with just as valid a solution - that is, of course, unless I missed something :)
Very cool little puzzle, thank you for sharing!