Being Japan, I won't be surprised if they ARE trained in ear cleaning...
I think you don't have to worry about your kids marrying some game character or something... They're still young right? Below 20, I guess? Plus, they don't live in a Japanese environment. ;p
I was a pretty hardcore gamer myself in my younger days. At one period in time (around age 13~16), me and my buddies were obsessed with anime, in particular female anime characters. We felt that anime girls were the best, as real girls have flaws. We talked and argued about which anime/game girl was better. ;p
I've grown out of it, though. Now, I play games mainly to kill time. I still watch anime, but I'm no longer obsessed with it.
Still, spending too much time on video games is not a good thing, though, and I can say that because I've been in your kids' shoes once. Just make sure it doesn't adversely affect their school and social life, and they should be fine.