MIGHT CONTAIN SPOILERS IF YOU HAVEN'T SEEN ANY HORROR-THRILLER-SLASHER-PSYCHO MOVIES EVER
Hollywood has never been shy of lifting, plagiarising, ripping-off or just plain copying. The genuine one-offs, the non-recurring phenomena, the true originals are scarce; the studios appear to come with a "Number Of Copies" button that you can just press and - voila - a "brand new" script. Some on the lower rungs, like the Asylum mockbusters (I Am Omega, Transmorphers) will be happy to recycle what was in cinemas two weeks ago (or if they're quick, what'll be be in cinemas in a few weeks' time); others may be more sneaky and xerox something that came out several years ago in the hope people won't notice. In this instance the film they've elected to knock off appears to be 1992's Single White Female, although a few minutes scrabbling round the IMDb suggests it sounds rather like the unrelated Single White Female 2 (which I haven't yet seen) that came out in 2005. Which is appropriate for a film about someone taking over another's identity.
The Roommate is named Rebecca: assigned to a college dorm with fashion student Sara, they start out friendly enough but it's not long before Rebecca is revealed as an insecure psychopath who wants Sara all to herself, and who will destroy, persecute or murder all who stand in her way. Ex-boyfriends, other friends, a leery professor (the last played by Billy Zane).... How long before Sara becomes aware of Rebecca's obsession? Answer: frankly, too long.
It's a 15 certificate in this country, but a mild one, just over the edge of 12A: in the States it was a PG13 so you know there's no meat to be had. No sex or violence and if you're going to going to have a psychological thriller about attractive girls going nuts and killing people, PG13 isn't anywhere near tough enough. It's soft and bland and doesn't deliver. The cast are mainly young and very pretty, though perpetually smirking male lead Cam Gigandet is particularly wet. Even the final reel's girl-on-girl punchup doesn't excite - because we've seen all this before, several times and much better. If you haven't seen all this before, it might elicit a few mild thrills at best. If you have, it's just going to annoy. And no-one's suggesting Single White Female was an unsurpassable cinematic achievement to begin with.
Compare and contrast: