I don't know how anyone could say that the original design couldn't work as-is in a game. Not to mention, we already have a horrifying character with an "abnormally human" design scaring the Hell out of people. The SLENDER man.
Especially if we're talking about motion. Bolaj Badejo worked his ass off on motion. Study this stuff,
http://www.youtube.com/watch?v=xpKi41a1rJI#Seriously, game developers! I love everything you're doing, but honestly, fix the suits design. It *can* work. All you have to do is get the exaggeration of the human form right, and make it move in a way that disturbs the player. It's not a brute or a beast. It's the devil himself, and it should look the part of Giger's original design from head to toe. It's criminal, especially if it's true they've been scanning actual props and set pieces from Alien, not to get Giger's suit at least 95% right.