Oh my I love this!
I study japanese pretty casually, but I think this could come in a lot of help for me and for other people
Or… at least I really like the sequence puzzle, I think it’s very neat! B3
If you haven’t seen this, maybe you could maybe get some inspiration from [Userscript] Niai 似合い Visually Similar Kanji ? As this also tackles the same thing you are currently, albeit in a different manner!
I don’t know, maybe there’s a wheal you don’t have to reinvent by looking at this
Hope this helps, good luck with the app!