Like all non-comedies about time travel, this movie becomes primarily about the mechanics of the plot devices and which corner our characters will get painted into to make the plot make any sense.
Like all time travel movies, this one basically falls apart if you think too hard about the mechanics of what they're saying and doing - and once the movie concludes and you have time to think on it - no, it won't make sense, but that doesn't mean I didn't like the movie. Also, no, I haven't seen Primer (I expect the comment section to get filled with Nag Troll Comments), but I basically expect for time travel movies to not really work as well as one might hope. In fact, the last one I thought did work pretty well was 12 Monkeys, which also sent Bruce Willis cartwheeling through time and space.
So what did I like?
That kid from Third Rock From the Sun has really come into his own the last 5 or 6 years. Gordon-Levitt seems to have catapulted himself into leading man territory and saved us from the gawky former Nickelodeon-star geeks that Hollywood insisted we were supposed to like. You will also be hard pressed to get me to say anything crossways about anyone on the cast, especially Bruce Willis playing Bruce Willis (who Gordon-Levitt manages to step into pretty well). Round it out with Emily Blunt, Jeff Daniels, Paul Dano, Garrett Dillahunt and you can tell director Rian Johnson pulled towards something other than a summer action-fest. Surely the studio would have rather made a thoughtless actioner, but did not and so chose to dump this movie in the September wastelands.
On two guys playing the same character: Somehow the make-up team and Gordon-Levitt really knocked it out of the park on making the character feel like a young Bruce Willis. Seriously. It's uncanny.
I also really dug the tone.
Look, nothing that happens in this movie is happening to particularly nice people, and the implications of the movie are pretty grim. Johnson gets that, and he stays true to that vision. This is a world where both our characters and seemingly everyone else has already made a lot of bad decisions, and the movie features characters making money off the worst of those decisions. When the past comes back to bite them, its a fairly dire picture. But: as cheap as life seems to be in the world of the movie, killing is something with weight that takes a toll on everyone in the movie. Nothing is played for laughs or taken all that casually.
Add in the weight of the set-up, and it's a movie that starts at bleak and goes downhill from there. And I appreciate that the creative team didn't shy away from the world they'd set up, the issues involved, and mostly dealt with it at face value, never heading toward a pollyanna conclusion.
I don't think the audience I saw the movie with knew what to make of what was on screen. I'd heard some stories about folks attending the new Alamo location near our house (from an anonymous source who may or may not work there), and this evening what I'd heard turned out to be true. They really did not know what to do with a movie that was not a cheery Expendables-style action flick. I even heard a guy behind me provide his own zinger during one scene, apparently frustrated that Bruce Willis was not spouting one-liners.
Unfortunately, within the first act the movie began to feel as if it was leading towards some inevitable places familiar to sci-fi and comics nerds who've read and seen their fair share of time travel stories (and the rest of the plot that reveals itself, what with its sci-fi elements). I wish that weren't the case, but I'm not certain what else you can do with time travel tales, especially ones that remains within the basic timeline of the protagonist's life - ie: it was not Bruce Willis launched back to medieval England or whatever. If Bruce Willis felt he'd lived all this before but it felt cloudy as a few details changed, well... I'm right there with you, buddy.
For all the havoc, some of the stakes seemed low. It's a weird thing to say, but once you're adapting and changing the past and future, some of the movie's focus on kids, wives, etc... despite many movies' tendencies to play to the understandable emotion of wanting to save your loved ones... somehow it feels tiny on the scope of the playing field. Maybe I'm just a petty jerk.
The script also had a few "studio notes" bits, like - our hero must have some quirk! He's learning French! It seems almost like character building! But, it's not. It's just something to distract from the fact that the character basically doesn't need much establishing but seems sort of like a block of Gordon-Levitt-shaped man-actor if you don't give some quirk.
Anyway, it was a fine movie. Too much is being made out of the "crazy" time travel and "would you kill Hitler?" implications, but that isn't a good reason to avoid it. Basically, the same people who got totally freaked out by Inception will probably struggle here (and I heard you in the audience, gasping).
Try to keep up, will you?