JESUS CHRIST. I am still digging my fingernails out of the arms of my chair. That was just a frigging fabulous bit of television. Scariest thing since "The Empty Child," and possibly scarier. I'll have to decide later, after a rewatch. Much, much later. Yours truly is a jaded viewer, and anything that gets me on the edge of my seat muttering under my breath, "Jesus, you dumb bastard, get out of there, run away, don't take your eyes off them, don't blink, dammit, DON'T BLINK --" is, um, enough to require that I calm down before taking another look at it and objectively evaluate it. But wow, that was a nice way to spend forty-five minutes, huh?
In all honesty, right now the only thing I can think is that it was pretty brilliant. Amazingly scripted -- the half-conversation stuff alone was worth the price of admission, and the guest actors they pulled in all had wonderful parts to work with; the guest lead was terrific, but even the smaller parts were wonderful. Especially the guy(s) playing the detective -- wow, great job all over. And the editing was top-notch. They really pulled off the effect of glancing away very well.
The only thing nagging at me now is the opening wallpaper message. Fabulously effective, but doesn't quite come together with the rest of the story.