Intentionally or otherwise, this review of the 3rd instalment of the series follows the actual script for the series.
In other words, just like the revelations that the central character must deal with in the story, we viewers also must cope with good news and bad news.
The bad news is that on the basis of pure entertainment, this is the weakest instalment. The fault here is that expectations were too high. The first two presented powerful and charismatic actors who popped in and out of nowhere. This sort of trope is missing here. The first two presented Nighy's character as a sort of white knight who potentially could bend an entire system to his will while he righted perceived wrongs. This final episode introduces reality into that hope.
The good news is that if you are going to narrow the focus of a film to the core stars, you could do worse than these stars. There is a scene near the close where Fiennes and Nighy finally get a face to face. It is a short scene but so powerful it could curl your hair without a curling iron. As it plays out, you realize the entire series was building to that one scene. Maybe Nighy's character is too naive for modern geo-politics. Maybe the extra eye candy is missing from this episode. Maybe the third Act is just about loose ends. But this is still spy drama at its best.