‘Tadashii Kanji Kakitori-kun’ is the one that I use at my Japanese Tutors house. It’s really fun and teaches you how to write Hiragana but mainly it teaches you how to write the kanji from Grades 1-6.
There is also another feature where you have to remember a certain kanji AND how to write it – it’ll show you a word (LEARN THAT WORD!) and you have to fill in the gap with the right kanji. (I can’t explain this one very well and I might be a bit off on some things as I’ve only tried it once for about 5 minutes.)
There’s also another feature which I haven’t tried yet.
I highly recommend this game although you’d probably need a mid-intermediate level to understand most of it.