The whole thing was introduced as cosplay by Cobra, and I think it was described as such by a couple of other posters before I even got into the thread. I am just telling you this to explain why I thought this was cosplay.
I think GPW mentioned he was creeped out as well, and I'd be interested to hear his reasoning.
Anyway, no I am not saying this was done out of sexual roleplaying or whatever -- like I said, I would have been just as creeped out had it been some adult dressed up as child character from a cartoon.
Had the role of the little sister been played by a child, I would have appreciated the whole thing without any apprehension. I can see that this person did this to showcase his artistic skills, and display his affection for the game at the same time, but he could have just as easily used a child in his family, rather than a female adult.
Thanks to your questioning, I've been doing a bit of self examination to understand what it is that I find so creepy, and I think I have come to understand what it is. Let me try and articulate it for you... keep in mind that it is 3 in the morning here, so don't mind if I sound more imbecilic than usual.
The things I immediately noticed from that first picture were the creases on that woman's forehead; the bags under her eyes; and the prominent cheekbones and nose, that all together presented a rough and unchildlike package. I am pretty sure that if you see a telling of the Peter Pan story, where the lost children are played by Joe Pesci, Hulk Hogan, and Carrot Top, instead of say, actual children, you'd be creeped out too.
But it depends on the context, doesn't it? If this imaginary Peter Pan story where Hulk Hogan, Pesci, and Carrot Top were playing the role of the lost children, was shot straight, you'd be creeped out when their opening scene would come up. But if it were a parody, then you'd probably find the whole thing fitting... though I suppose you'd still be creeped out considering that Pesci is dead.
The thing with this piece of art is that it looks so fucking authentic. The lighting, the costumes, the background etc., are all brilliantly done, and highly detailed. If you look at the little sister's costume, you will see it is dirtied in the right places, while The Big Daddy looks as professionally done as he would in a proper movie. In that context, she looks totally out of place, because my mind naturally expects a more authentic representation.
I guess what I am saying is that the whole thing is too good for them not to have chosen a better representation of a little sister. That's automatically what my eyes drift to.
The funny thing is that had the Big Daddy looked half assed, or the background looked like a typical back alley in the guy's city, or even a part of his home, I would have found an adult playing the part of a little sister far more acceptable.
You know what this almost looks like? It is so good that it looks like a screenshot from Bioshock, with some dude having photoshopped his girlfriend's face on the little sister's body.
There is also no doubt that I am a self-hating geek, who finds it 'effed up that adults would wear costumes and stuff to tribute a game they love. It is just the way I am... I can't help it.
