I'm kinda torn on what to say you should do. You'll wanna be able to get through your Halloween without having to explain your costume to someone every five minutes (believe me, I know what that's like). But on the other hand, you should also be able to dress as something you want to dress as and not worry about other people.
it's not natural. i wish it was. it's kinda close to my natural color though. my hair is a bit darker, but it does have some red tones in it. i was thinking of just doing all purple though. easier for upkeep, u know? i'm lazy lol
The Bioshock costume idea sound great. The people that will get it, will think it is a great costume idea. Those that don't get it, well, they don't play mainstream video games. It might happen. If you want my advice, I say do it anyways and don't worry about not being understood.
I'm always wearing geeky t-shirts and (on the few occasions when i do dress up) costumes. I love the fact that most people don't get the jokes/references. It makes it that much more special when they do. I always know when I've found "my people"
That said, I hardly play any video games and even i would get the Bioshock reference. They've become pretty iconic characters.
As for the Bioshock reference, I think it depends on where you plan on going. It's a pretty well known game though so I would think that a majority of the people will get it. If you want to be safe though, bring a copy of one of the games, the console of your choice, and a television to show anyone that doesn't understand.