Standard warning: possibly contains MILD possible spoilers. Read at your own possible risk. You have possibly been warned.
Let's get this part out of the way first. If you're only reading "Jacket" reviews to find out if you really get to see Keira Knightley topless in this, here is your answer: Yes, two partially-obscured sideviews in the 2nd act, but it's quick enough that most of you will have to wait for DVD (or for MrSkin.com) to see anything.
Here we have Adrien Brody in his first big high-profile "mainstream" release post-"Pianist" and pre-"King Kong," in a metaphysical psuedo-scifi film that, for a change, is actually much more accessible and "normal" than the trailers would lead you to believe. Those who go in anticipating a "Slaughterhouse Five" or even eXistenZ"-level mindscrew may even find themselves dissapointed to instead confront an almost "routine" time-travel yarn which finds it's "hook" not in what it adds to the paradox-toybox but rather in what it leaves out: The "mechanics" of time-travel; and the explaining, contradicting and re-explaining of which typically forms the bulk of any time-travel story; are almost nowhere to be found. The film presents a roughly-defined "procedure" through which a character is able to leap back and forth in time that works simply because the film says it does, and beyond that is chiefly content to sit back and observe how it's characters react to the situation.
The time-skipper in question is Brody as Jack Starks, a Desert Storm vet accused of a murder in 1992 (where/when most of the film takes place) for which he may or may not have been framed. Believed to be suffering from Gulf War Syndrome, he's committed to a hospital for the criminally insane where a doctor (Kris Kristofferson) uses him as the subject of a strange experiment wherein he is pumped full of powerful drugs, bound in a strange restraint-jacket and left inside a mortuary drawer for hours at a time. For reasons unknown, these stays in the drawer send him hurtling into the year 2007, where he continually crosses paths with a young woman (Knightley) whom he met as child back in 1992 before he was committed. Soon, he's hopping past-to-future regularly, trying to prevent his (2007-confirmed) death or at least figure out the cause of it. A second, more-ethical doctor, played by Jennifer Jason Leigh is also on hand in what would be called a red herring role if this were the whodunnit-thriller the trailers are pitching.
And... thats really about it. Not a lot happens in "Jacket," plot-wise, which is going to grate on a lot of people's nerves. The premise here seems to be less about exploring the possibilities or theories of time travel and more about exploring what Starks' ability to jump through time does to his relationships with the characters around him, and vice-versa.
Much of the 2nd act is devoted to Jack meeting 1992-people as their 2007-selves, being told about some amazing life-altering insight he offered them back in 1992, learning what it was, then going back to 1992 and offering it to them, just like he'd heard himself do... in a standard time-jumper movie the whole plot would spin out from trying to unravel that kind of circular-paradox, ("if he told them in the past what he knew from the future... but then how did it happen the first time... because if he..."), but "The Jacket" skips over any such discussion entirely (perhaps in the interest of keeping the majority of audience members' brains from liquefying and running out their noses) because it really just doesn't care "how it works." It just works, and with that taken care of the film stays on it's main track of watching the changes characters go through when confronted by a man who has met them both before AND later.
"The Jacket," then, is an unusual film being billed as an out-and-out "weird" one, which will probably be to it's detriment. There's a lot less going on than many people will want, and a lot more than others will be able to take. I reccomend it, but with a caveat: Don't go expecting it to be one thing or another, just let it "be."
FINAL RATING: 7/10