This chart details the complex process video game designers use to determine if the villain should be a Russian or a demon. As for the female characters, it's a one, or rather, two-step process.
I don't disagree with anyone's comments that the cases of over-sexualized women in video games vastly outweigh the cases of women who are defined first and foremost by their badass-ness (nor have the exceptions slipped my notice,) but I just want to add a simple point:
The men in these games are also idealized. Adventure protagonist—shirtless? Well you know the man doesn't have man boobs, at least not the floppy kind. He has, almost without fail, a 6+ pack, great ass, broad shoulders, etc. And let's be real, I've seen some damn nice jaw lines in my days as a gamer (to each their own!)
Now two wrongs certainly don't make a right, but before we vilify all male game developers (or at least that's who many assume are making these female characters), I think it is at the very least interesting to point out that men don't escape the idealized touch.