Same goes for the other characters. Vamp is a vampire so that he can survive a bullet to the head and run on water. That's it. It doesn't really effect his boss battle in any way. He's just a guy who can jump around a lot and negate first person view shooting. I guess he can also "freeze your shadow" but is that even a vampire power? He doesn't suck your blood to regenerate his health or turn into a bat or seduce Emma or do any real vampire shit other than drink a SEALs blood in one cutscene.
If Snake is to be believed (when he explained to Raiden) Vamp didn't get his codename because he's Eastern European and vampire themed. He got it because he's a big slutty bisexual, and Kojima fervently believes "vamp" is slang for that.
I agree with your insight. I think that there can be a slippery slope, mood-wise, with the supernatural. It's easy to fold one ESP user per game into the mix; for some reason, that doesn't clash too badly with semi-sci-fi. Dude has lightning powers for no particular reason, well, lightning looks like electricity and it's a research base; it's fine. You start getting ghosts and maybe-vampires involved, I could see how that could feel like it's getting silly, from a writer's perspective.
(In the comic for MGS2, the ghost of The Sorrow turns up to briefly tell Ocelot
SON I AM DISAPPOINT that Ocelot is not better at handling attempts at possession. It's great.)
Actually, it is an odd example of restraint that we didn't get a huge CODEC or cutscene explaining very specifically why Colonel Volgin has lightning powers. We were told why Volgin has his political power and a ton of money, but shooting lightning, that's self-explanatory. It works well like that, too; maybe Kojima learned.
