I picked this up last Thursday and I think overall I'm quite happy with the game.
First, my background. Three or so years ago I used Heisig's Remembering the Kana
to learn hiragana and katakana, used Pimsleur Japanese 1 and 2 to learn basic spoken conversational Japanese, and then had a 3 week trip to Japan to cement the real basic conversational language. I dabbled a bit in kanji but didn't go much past the first or second grade level.
Now here I am several years later jumping into My Japanese Coach with a lot of my prior Japanese knowledge getting rusty.
The game starts you off with a placement test. It doesn't really test your overall knowledge to then place you; it basically goes sequentially through the game's lessons giving you a pop quiz on each lesson's subject matter. If you miss two questions in a row you're placed at that level.
I breezed through what seemed to be basic greetings and phrases vocabulary, some basic numbers, and then got two wrong in a row when it got to colors. I did need a lesson in colors since I only knew 2 or 3 going in, but overall I don't think it was an accurate placement for me. I'm now on lesson 19 and aside from a few new vocab words here and there it's mostly all stuff I already knew. Still, it's been a good review.
Once you get a few lessons in they start throwing hiragana (the 46 character alphabet) at you. One lesson will be 10 hiragana characters, the next will be 10 vocab words, then back to 10 hiragana. When I hit the last 46 characters they started throwing in katakana, the other
46 character alphabet. They just progress through the kana alphabetically; I think it would be much better if they gave you building blocks for simple words so that you could reinforce the kana through real application.
It's been a great, great review tool for me, because while I can read hiragana and katakana pretty well I've hardly practiced writing it and I have a hard time recalling characters from memory. I'm really not sure how well the system would work for people seeing the characters for the first time, though. They stress the importance of stroke order, and they do show you the proper stroke order, but when you're actually being tested on your writing the handwriting detection doesn't care at all what order you use, and won't even mention if you've written it in the wrong order.
In addition, the game doesn't really prompt you to review previous material. You have to take the initiative to play games for old material even though you won't get any 'points' to reward your effort. If this is all new to you, and you just follow the lesson progression, I think there's absolutely no way you'll remember the first 10 hiragana by the time you get to the last 10, let alone by the time you get to the last 10 katakana.
There's some problems with the games you play as well. The whack-a-mole game, for example, seems like a good idea but in practice over 50% of the moles that pop up display the word that's being tested, so as soon as you see a lot of one word or character you know that's the right one. You could test me on ancient Egyptian and I'd be able to ace the game on the first try.
Still, if you stick to the better games they do work well as learning aids. I pretty much stick to the flash cards for vocab, the 'fading characters' game for learning how to draw new characters, and the 'write cards' game to memorize the new characters. I've only unlocked half the games so maybe there's some more gems to be seen down the line.
Right now I'm really really happy with the game for what I'm looking for, which is a fun way to expand my vocabulary and get more practice reading and writing kanji. I don't know how well the game would work for someone's first introduction to Japanese unless you are good at setting up your own study regimen. I think buying some supplemental study books would really help the game work, because from the looks of things I doubt the game is going to do a very good job explaining how kanji characters break down. I'm guessing they'll just be throwing 10 new kanji at a time at you, but since I haven't gotten to any kanji yet I shouldn't be so quick to judge.
I'll stop there since this ended up a lot longer than I expected, but I'm really curious to see how the game holds up to you folks learning the language for the first time.