Boring is such a hollow pejorative as much as nice is a terrible descriptive. Yet they have their uses. A review is nothing but a snapshot of what one person thinks, arbitrary, tainted by not just personal preference but by whether they had a good meal that day or where squirming through a film needing the toilet. You can try to separate that from the film itself but a hundred million things can affect you a hundred million different ways.
That's my way of saying, despite some good performances (Tatum and Ruffalo are excellent, Carell is fine but it feels like acting with a capital A, directed by his make up as much as anything else) and an eye for the odd interesting composition the film is, well, all kinds of dull.
It keeps itself too removed from everything. Parcels out plot (almost non existant) and character beats incredibly slowly. Perhaps hoping to build a sense of dread, especially if you know anything about the actual events that happened but it never seems to serve any purpose.