It's a quite a different movie — though the "plot" of La Jetée remains more or less intact, it's more of a framework on which other plot threads are hung, or warped around.

I understand it's less of a remake than a starting point; I think La Jetée will still need to fade a little before I can see it.

Brad Pitt and Bruce Willis both give remarkable performances as the mentally disturbed antagonist and protagonist, respectively — you can see why they wanted to be in the movie, because both cut hard against their popular personas.

Which is always very cool. (Even if my sole experience of Brad Pitt and Bruce Willis is Snatch and The Sixth Sense, respectively . . .)