Three Stars mostly due to lack of innovation over the previous game and the issues of this game using the previous game's structure while covering a much more difficult subject matter. When it comes to Hiragana and Katakana they're much more digestable, 5 a batch and just knowing what the Dakuten and Handakuten do to the letters. Kanji on the other hand get no such luxury, and you're flooded with 5-7 completely new words each time, many using similar ways of saying them. They are made from similar pieces but you're rarely ever given the building block kanji first and can be sent into the big boys right away.

Furthermore, the bonus content from sidequests is just more Kanji. Where as previous games gave you sayings and sentences so you could see the letters in action, and sometimes had things written in hiragana and katakana throughout the overworld that rewarded you for paying attention, kanji only get 10 that have that luxury as currency.

The currency system and upgrade system feel poorly thought out. There's 10 total and if you upgrade the fountain each time, you can exchange one for its counterpart. But there's no way outside grinding and praying you get the ones you need, so have fun hoping to god you run into Water coins given all the objects that need water upgrades. Meanwhile Fire, Stone, Wheat, Rice, and Tea currencies are rarely used for anything so you'll have half the currencies just sitting around.

Combat is easily avoidable thanks to the really dumb AI and even if it wasn't, combat feels incredibly stripped down from Katakana War. (which was already simple) Gone is the Magic system that gave MP a purpose, and they gave what people requested: All the enemies die in one hit. The problem has several layers to it:
-Offensive stats and weapons are now pointless because all the Kanji die in one hit
-The only stat that matters now is Speed: You can kill them before they do anything meaning all you gotta do is go first
-This means Party members basically don't matter and while they weren't exactly role distinguished before they had hints of it (Charlotte was clearly a healer) now all that identity is gone and party members are solely based on who you like seeing
-This hurts retention since I'm not reinforcing what the answer is, I'm just hitting the Kanji and moving on with it
-This only encourages avoiding encounters because you don't have to grind anything really. Further enabled by how easy it is to do.

And all in all it made the Kanji Combat feel more like a matching picture game than actually learning a language game.

The story's the same alright but while I wouldn't say it has anything that gets dark I'll say it gets needlessly grim at times, sometimes in ways that came across as comical to me (all these trained veterans died in the katakana war, the easiest thing on earth handled by clueless morons how) and even an onscreen murder or two I was supposed to learn Japanese right?

All in all I entered this game thinking Kanji was insurmountable but tackleable, just like Hiragana and Katakana. But the little girl was right.
I cannot learn Japanese.