We have tried many kana apps, and this one is hands down, the best. It’s fun for my kids (keeps their attention with pictures), has variety in the games, instructs in Japanese (which you can read in either English, Thai, or Japanese), and spells out words.
I like that it repeats each kana in different ways after learning how to write them. It’s fantastic that it constantly says the pronunciation of each kana as you’re writing it.
The only thing that I would update would be to say the entire word after it is spelled out, such instead of just saying each kana. It’s not clear to little ones what the word is since they write slowly.