Anyone who gets offended by something like that probably isn't worth your time. My Japanese friends all think it's kind of cool that I learned their language from videogames. :'D And some of them learned English for stuff like Twilight and Harry Potter, anyway, which is basically the same deal. As far as I'm concerned, there's really no valid or invalid reason to learn a language. And by my experience, the people who preach such elitist attitudes rarely get very far with language learning to begin with.
In short, so long as you don't go around telling Japanese people off for not knowing who Cloud Strife is or asking them if they think Miyamoto is the most important figure in Japanese history, then chances are nobody's really going to care why you're interested in learning their language.
On the contrary, I've found that most people are just really happy that you are.
In any case, good luck with Japanese! I've had so much fun studying the language, and I'm always happy to see other people taking it up. It isn't nearly as hard as some people would have you believe, and if I can learn, there's no reason you can't too!
Feel free to ask if you ever need help with anything~
On topic, there are a number of Chinese RPGs I'd really like to play at some point. Chinese games tend to be pretty low budget and by the books gameplay-wise, but the settings, stories and art styles take a quite different approach to Japanese games, leaning heavily on Chinese mythology, history, and wuxia movies and drama. There are a few I own in particular that seem really fascinating. And I'm currently making decent-ish progress with Chinese, so maybe in a year or so...