Most Ipod applications for Japanese are either dictionaries, kanji or word memory cards.
There doesn't seem to be anything equivalent to the Japanese games for learning English, where for example you have to put a jumbled sentence in the correct order, translate a sentence from English to Japanese, or pick a correct word for a sentence (similar to JLPT questions).
Is this something Japanesepod101 can offer?
Best Regards,
Sam
