Brilliant for improving areas you never thought were wrong!
This is one of the first kanji-learning games I bought for the DS and I still play it everyday.
It's great for continuous learning as the teacher will recommend that you take a break after studying 10 characters.
Ideally you should be able to read hiragana before playing this game or you will find the instructions very difficult to follow. However, writing practice for both hiragana and katakana, as well as all of the kanji needed to be fluent in japanese (Joyo list) are included.
I had already studied about 500 kanji before I started playing this game but that is no guarantee that they were perfect or even that I was able to remember all of them!
The game will ask you your age when you first start it and it's probably not a good idea to enter your real age as the game is aimed at native Japanese speakers. I entered myself as 7 years old in order to get a suitable level. However, the game will also give you a level check or you can choose to work through everything from the beginning regardless of your level. This is what I chose to do. I usually practice 10 characters aiming to get my score above a certain per centage before moving on. For any unfamiliar kanji you can touch the book symbol at the top right of the screen and it will provide you with the main readings plus a simple explanation in Japanese about what the kanji means.
The order that textbooks for foreigners learning Japanese teach kanji and the order that Japanese children learn in is different so you may be surprised that there are quite a few kanji at the lower levels that you may not have studied, even if you ahve learned some kanji before.
I'm still discovering new features of this software and would highly recommend it to anyone, even if it is just for ten minutes on the way to work or during a coffee break - it is easy to pick it up and learn something in such a way that your skills will improve without you really noticing that you are studying!

An absolutely Brilliant learning tool!
I own the prequel and the new features turn a really good program into an amazing one.

The new diagrams to show what you did wrong when drawing a character are really easy to understand. Though if you draw a stroke backwards, say right to left instead of left to right, the diagram is sometimes in the wrong place. Doing the strokes as the animated diagram in the program does avoids this entirely.

The new readings section is brilliant!
It gives the ON and KUN readings and many examples of words using the kanji.

The testing in the game is great though some more knowlege of japanese is needed to do them with much ease.

This is a must for anyone learning kanji.

Great learning experience
This is a great learning tool, if you at least can read hiragana. I bought it because a few months ago I started learning Japanese.

When you first boot the game it asks in which grade you are (from the grades of Japanese school, 1 the first year to 6 the sixth), then it gives you a level test so that the game can figure out where you should start, after that it shows the normal menus for hiragana, katakana and kanji.

It has all joujyo kanji (1945 kanji, including meaning and way of writing them correctly) along with hiragana and katakana in order for the user to learn how to write them correctly.

For example, in hirangana, you write the symbol for "a" and then tapping on "correct" button it gives a grade between 0 and 100 (being 50 a "pass" and 100 "perfect"). What's more interesting is that the sotware tells you the spots you got wrong and how to fix or improve them, it's like a Japanese teacher on the go.

To sum it up, if you are learning Japanese; I recommend you to get this game, it really helps a lot.