Well tough luck I guess. Emmerich being in the game isn't a surprise or twist. He's the only one in that age pretty much capable of creating a Metal Gear. It would be like Otacon being in a Solid Snake game.
I know, and I don't disagree that much really. The more important thing is what I said immediately above:
The main thing is, though, I'd still argue that sayingis a far bigger spoiler than simply saying'The mission where you get Huey''Huey is in the game'.