As a piece of linear narrative it is an odd tale, but the shifting in time gives it a deeper and more palpable sadness, a horrible view through a rear view mirror of how the past contributed to the mess of the present day.
Everyone you knew who had seen it had theories, some of the more outlandish ones even turned out to be true. It kept you guessing right until the very end.
My favourite TV review site, Den of Geek, has this superb loose end gathering.
Here are mine:
Lt Stone was faking his dementia, it helped him not have to confront the fact he'd led his friend to be killed and it protected him from the horrors he saw in Iraq.
Nadia Herz was up to far more than losing control of Adam Gettrick and her squad.
No-one has quite answered why Daniel Reed wanted to fight for the Peshmerga when his unpaid debt was to a family of a Saddam Republican Guard. Clearly the shadowy figure tailing Baptiste was a red herring, but it suggests deeper corruption and malpractice from 1991.
Did Daniel Reed survive?
Will Matthew walk away from his grim German pals if he escapes prosecution?
Though there is no doubt in my mind at all that Julien Baptiste has survived. Series three may be a couple of years away, but we'll need it after all that excitement.