"The actors are our vehicles for emotion. We need to make sure that we capture every last bit of their performance and translate the emotion into the game. You know, getting 80 percent of that is quite easy. But after that every additional percent takes a lot of effort," Cage says. "Right now, we're working on lips and the revealing of teeth. It's incredibly complex, a matter of fractions of a millimeter, and if it's not right you'll immediately notice. We're also working on the tongue. You may not think you see my tongue moving while I'm talking, but believe me, if it stopped you would be horrified."

Quantic's latest milestone is a new system for eye movement, completed in September. Eyes can't be motion captured, since you can't attach markers to them, and Quantic has been experimenting with video tracking, struggling to perfectly capture the minute movements of a living eye. Cage is visibly proud as he shows me two bloodshot eyes gazing out from a 28-inch screen, restlessly moving, blinking in soft, rapid motions.

"This is in the engine. It's not CG, it's in the engine," he says. "It's really alive. It has soul. Soul is in the eyes."

With such devotion to detail, it seems odd that Quantic employs only three animators, but this is a consequence of Cage's philosophy of keeping performances pure, captured by high fidelity technology and preserved in pristine condition. "As soon as you start touching up an animation, you kill it. Life is a very fragile thing."

To some, the illusion of life is so fragile that the slightest aberrations destroy it. Some flinch at the sight of Mary Smith in "The Casting" because of slight glitches in her facial movements. There's a botox-like rigidity to her upper lip, a vaguely disquieting quality in the clipping of her eyelids - little things that would go unnoticed if her body language was more stylized, but are jarring in such a lifelike performance.

The unease caused by artificial humans that are close to, but not entirely, realistic, is often called "the uncanny valley," a term coined by Japanese roboticist Masahiro Mori in 1970. According to Mori's theory, a replica of a human will elicit more empathy the more realistic it is, up until a point where the simulacrum becomes so lifelike that small faults pop out and make it seem uncanny. The "valley" is a dip in a graph that describes the level of familiarity one feels with the simulacrum.

But the uncanny valley works differently for different people. "The Casting," for instance, divides people into two categories: The critical-minded gripe about disturbing flaws, while those more willing to suspend disbelief are amazed at the depth of human emotion expressed by Mary Smith.

Jens Matthies, the Art Director at Starbreeze Studios, has an ambivalent relationship to moving faces and the uncanny. He explains over the phone that he subscribes to Mori's theory and holds a pessimistic view about the long climb out of the valley. Still, Starbreeze worked hard on the facial animations in The Darkness, going as far as developing a proprietary system for facial animation, a process Matthies describes as "insanely laborious."

Matthies and his colleagues dubbed their method "VoCap," since it captures voiceover and motion simultaneously. After spending lots of time developing the system, they set up shop in a sound recording studio in Santa Monica, California. The process was fraught with unforeseen problems, like finding a mocap suit large enough for a 350-pound mob character and creating workarounds for limitations in the studio equipment.

Comments on