I just finished the Japanese tree! :D
I wish it was longer, had more kanji, and had fewer errors. But overall I still enjoyed it. Hopefully, we will get more content updates soonish, and possibly a PC version.
Congrats! I could probably have tested out of more of it (I took 2 years of Japanese in college), but I wanted to refresh myself on some of the vocab and also wanted to help work out any bugs/errors in the tree, so I'm taking it slow :)