What if you could learn to read Japanese by playing a console style adventure game? Darrel Johnson of LRNJ (LeaRNing Japanese) would like you to do exactly that with Slime Forest Adventure.
Available as a free download for Windows, OS X and Linux, Episode 1 of Slime Forest Adventure teaches you all katakana, all hiragana and about 200 kanji. It also tests you on all kana and 100 kanji.
A $20 U.S. membership gives you access to the member version of the game, which includes a second episode with nearly 2,000 kanji. That's enough to bring you up to full adult literacy. The episode also features new islands and quest mechanics. Successfully learning 200 kanji will win the game.
Darrell is currently working on integrating an improved battle system, reorganizing the kana curriculum, sorting Jouyou kanji into better mnemonic order and adding example vocabulary. The $20 membership will include future updates and new episodes.
You can download the free version and sign up for the mailing list at the official web site.