The story left a lot of questions and the ending was not well thought through.
Even with the neat setting of an ancient, claustrophobic submarine, "Phantom" still does not manage to be anything more than just the idlest bit of speculation, Cold War division. That's fueled by gigantic leaps in logic that only serve to keep the plot moving before an ending that truly beggars belief. At least, William Fichtner does his usual very fine work while Ed Harris does some subtle acting here. On the other hand, we get even more proof that David Duchovny cannot act.
The movie is quite engaging once we get the sub in the water. Harris is quite good as his character struggles with internal demons. And I have always though William Fichtner is under appreciated in Hollywood. But I was bored about 45 mins into the movie.
Where was the film going? The pacing was majorly off and that is deadly when making a thriller. It's sink or swim. And this boat sunk. (3 out of 5) So Says the Soothsayer