All I'm taking away from this is that every protagonist, in every crpg ever made, was a Mary Sue. This despite the fact that some people will have all the cheat codes printed out beside their monitor before the game ever installs, just so they can't mess up. This despite being "saved by the bell" aka the infamous Quick Save, just in case they pick the wrong dialog. But wait, if the character is truly a Mary Sue, there can't be a Wrong Dialog, can there? That would be totally out of character for a Mary Sue.
That is, as I see it, the problem with trying to attribute a literary trope to an interactive medium. The vast majority of video games are written in such a way as to allow the PC to successfully complete whatever it is they're supposed to be doing. Why? Because if it was possible to get the "Game Over" screen 5 minutes into Chapter 1, that games forums would make the old ME 3 boards look like Hello Kitty forums, all sunshine and rainbows. Yes, you get to solve the problems, because if the devs didn't let you solve all the problems, you'd be saying how epic fail the game was that you could, inadvertently, "break the game" and fail by choosing the wrong line of dialog, or going to the wrong map first, etc etc.
So no, I don't see video game protagonists et al as being Mary Sues by design. I see gaming companies making it so that the player can win the game in order to protect their bottom lines. Somebody pointed this out earlier, but it bears repeating: Any time a PC is shown to not be invulnerable, it's a fail on the devs part. The examples given off the top of my head were ME 3 Shep and Hawke. Two characters that "wore their flaws on their sleeves" as it were, and were bashed to hell and gone for it. What was the most common complaint? Roughly paraphrasing here: My Shepard/Hawke could have solved that with no problem, wouldn't have been emotionally affected by the death of a crew mate/family member. Yes, there was a poster in the DA II forums that stated flat out that he/she wouldn't have been upset about his/her mother dying. So games are written the way they are because if they weren't, people would be all over the place shouting at the tops of their typing voices about how fail that game developer was.