This film promises sheer terror in the face of a nuclear attack from an unidentified attacker, and the first 35 minutes builds tension and leaves you hanging on for dear life. Switching between the crew of an Alaskan missile silo and the group chat of the Pentagon; we see and hear the rising desperation of the White House and military as events unfold. It had me truly invested in what happens next.
Unfortunately; what happens next is the first 35 minutes (and conversations) repeated twice more from the perspective of those whom you heard, but didn't see.
What doesn't happen next is any kind of resolution. You don't know what happens next, because it only ever gets to the point before a possible strike.
In essence; whatever tension and character investment the director builds in the first 35 minutes is slowly undone by the third act. I actually started singing the opening words to "I Got You Babe" to myself when I realised we were starting again for a second time.
If you want a tense film about the dangers of an unexpected nuclear attack in todays paranoid world of mutually assured destruction: try War Games or Twilight's Last Gleaming. They, at least have an ending. This is just Groundhog Day with no end in sight.