The Double is more stylistic than effective as a piece of cinema, but it's pitch-perfect in mood while it evokes shadows and this sort of twilight world that seems more appropriate to a photography darkroom than reality. There are hints of Gilliam and Lynch in some of the stark sets and I was reminded more than once of both Brazil and Eraserhead.
The movie also, funnily enough, reminds me of a Buffy the Vampire Slayer episode where Xander is beset by a doppelganger who seems effortlessly confident and bent on usurping everything in his life, from his work to his friends. At the end of the episode however, Xander finds that the doppelganger isn't an evil clone at all, but that he's actually been split into two people and the two complete each other. Eisenberg's character and his acting is much like this -- his double seems to represent everything that he lacks. Furthermore, Eisenberg's acting is familiar and falls back on his geeky awkward persona until the introduction of his double where we get to see some more of his chops (albeit in a very jackass Social Network manner).
Wasikowska appears to be the dark indie darling these days, what with Stoker, Only Lovers Left Alive, and now this. She plays the role well, but it's bland to see the same face in the same sort of movies over and over again. I almost want to see her in a chick flick to see how she'd do.
The movie has some great gags, but mostly lacks in script and the almost pedantic storyline. It does make up for it in visuals though and some arresting imagery. What happens when you are left faceless as it were -- when your appearance is the basis for falsehoods? Eisenberg cries out "he took my face" at one point in the movie, and there's a visual theme of these facial features. When Wasikowska looks at herself in the mirror or draws a self-portrait, she's unable to see her face, but only the back of her head.