That Criminal Girls shit? Man.
Lemme just say this. I have a friend online who has pretty frequently defended "otaku games" in blogs and articles which some of you may have read, many of them the ones prominently featuring prepubescent girls, though I'm not sure any of them are as egregious as Criminal Girls. Maybe most "otaku" and "moe" games don't actually cross that line. Every freaking avatar I've seen him use over the last several months has been like, an Atelier character or something. His basic argument has been that a lot of those games actually have great gameplay. I've seen a lot of people defend moe anime by saying some of them are quite well-written and that those girls actually get lots of character development.
Personally, I think if that's true, then they could stand to lose the over-pandering fanservice and let the other qualities stand on their own. As has already been said, that shit is considered weird even in Japan. It's laser-targeted at a VERY specific audience as a response to economic shifts. Many Japanese developers (and anime producers) gave up on mainstream audiences, and the result has been increasingly insular content. I won't 100% condemn such games until I've played them. All I'm saying is they don't make the barrier to entry easy.
I wonder how Japan in general will react once that shit is considered a crime.
This is where a huge problem lies. The Japanese government already tried to make this a crime, and the entire manga industry revolted. Even well-known dudes like Miura (Berserk) came out against the law. OT had a huge thread about how virtual depictions were eventually left legal. The manga industry's argument was that the law was too vaguely worded, to the point where almost any manga featuring any sexualized characters could be banned because of how difficult it can be to tell a virtual character's age.
The Dead or Alive games already change the ages of their female characters in territories outside Japan for just this reason (Ayame and Kasumi are technically teenagers). And I'm sure other Japanese games do things to skirt around possible controversies in different territories. I think Hideo Kojima's own Snatcher was censored in the US for this reason (one character is 12 in the Japanese version and 18 or something in the US version).
Basically, actual enforcement could be a troublesome grey area.