And this is true of both the characters in the movie and the viewer. Well the latter should rather try to enjoy as much as possible. Because the science behind it all does not really mix well together. A problem that the movie is not alone with. Mingling with time and trying to make it plausible is almost impossible. Just a few have managed to get the "technical" things right or rather the things right that would seem logical.

But throw logic out of the window, because this is about teenagers. And while you get the obvious "what would you change, if you could" discussion, in the end it all boils down to personal advantage (mostly). And can you blame them? The twist at the end is kind of redundant, but it's there and better than the alternate endings that can be watched on the disc/special features. Enjoyable if you don't think too much