I am torn on this one. It is hard to say if Travolta's performance as a man "on the spectrum" is inspired, unhinged, off-base, insulting, or respectful. (Keep in mind, Travolta's late son Jett was autistic, so presumably, this would have some influence on how he chose to portray this character.) His performance is not the "train wreck" some have made it out to be - but I'm not sure just what it is - though it is worth watching.
The story, though, is pretty garbage with odd lapses in logic and just poorly written, overall. This is not a good film.
Nicely done take on a time-travel-esque story that has been done before. There are a couple of points where it wanders into stupid territory (with some greviously injured characters stumbling around for far too long) but all-in-all, it has a good emotional core that makes up for it and makes it worth watching.