It's one of those overly sad docs that focuses on the suffering by the victims. Americans really cannot make a proper 9/11 documentary until maybe 50 years have passed. They are all lacking info and focus on tears and emotions. It's hard to understand what exactly happened unless you read technical papers because they still don't care to explain it. They feel it would be too cold to just go over the facts and technical details so even 20 years later we still get these docs that are glorified memorials.
This doc is a bit above the usual 9/11 stuff, the pacing is fine, and you have some potent interviews with the family members. It even goes into the "showy" style at points. With the 3 first flights that crashed into buildings you really don't have many calls or info. What we know from the planes is what we have seen in basically all other docs. Here they just have interview with new family members and writers. But from the cockpits and the ground we get minimal info. Combined the info here would take up maybe 5 pages in an article at most which really is not good enough. I spent 2 hours watching this so I expected to learn new things. The showy style appears when interviewees go a bit overboard and try to make up stories about what happened on the planes that did hit their target. We have a guy tell us that a former soldier on a plane surely attacked the terrorists and was killed by them. No evidence is given to support this claim whatsoever. It's just a story he made up. Why include it? Because it's showy and you don't want to give us actual technical details.
With United 93 we have more calls and the crew actually trying to storm the cockpit. It was a later hijack so the crew had info about what was going to happen and they made sure the plane would not reach the Capitol. So at that point we get a bit more info in the doc too. But it's a small part of the doc and the black box was never made public so even here they focus on interviews with family members.
It's an emotional doc, sort of, 9/11 is a long time ago. The interviews are good as they are not too slow. But it's still stuff like: "I lost someone I cared for and that person was amazing and I miss them."
It's hard to fairly rate this. It's 6,5 stars. Not boring or pointless, but you also have to ask yourself why this was made if they don't even care about going over all the smaller events that happened in the air.