Wow where to begin? Well there's so many areas of fiction in this film that knowing where to start is a tough one so lets start at the beginning. I bought the Horse Soldiers book way back in '09 when it was released and the reason was that during my time in the RAF I was sent to Oman in Oct '01 as groundcrew on the AWACS aircraft which was co-ordinating all the ground-strikes in Afghan so I got to listen to these missions as they happened and wanted to know more about these guys on the ground.
Anyway the book is the actual story of what happened and it's against this that the film is judged. TBF everything up to their actual insertion into Afghan is accurate but from the minute their boots hit the ground the fiction starts but the biggest single issue is that Nelson (Hemsworth), for the last 1/2 of the film, wasn't alone with the Afghan General Dostrum as the film shows and for most of the last 1/2 he wasn't even within a mile of him. Instead Nelsons superiors Lt Col Bowers (played by Rob Riggle) and
Major Mark E. Mitchell (not shown in film) were airlifted into Dostums camp about 5 days after Nelson arrived and it was Major Mitchell who accompanied the General everywhere earning himself the Distinguished Service Cross (the 2nd highest bravery award) for doing so, the first issued since Vietnam. So Nelsons ODA team were not alone there were infact around 50 other US SF troops embedded with Dostrum, who also had no problem with the "other" warlord who had an embedded US SF team (in the film he has a hissy fit and leaves when he find out about the other SF team), the SF troops didn't engage the enemy in a cavalry charge (although they did engage the Taliban directly), Michael Shannons character never was wounded by a surrendering Taliban (complete fiction) and the list just goes on. What these guys did IRL is amazing and I just don't see the need to Hollywood to think "Nah, not brave enough, lets make some stuff up for drama" with a story like this!
This is my problem with Hollywood - ****IF*** the story they tell is based on a real one ***AND*** they are portraying the real life guys then they have a responsibility to be honest. The real people involved are now going to have friends and family etc asking them "did you do that" after watching this film and for almost 95% they'll have to say "nope, it's all made up". The story is amazing enough without having to sex it up with lies! I had the same problem with Blackhawk Down which makes the film version of Sgt Eversmann into the focal point and the main hero while IRL he wasn't there for 2/3's of the action as he went back with the first convoy, yet in the film he's shown doing all manner of stuff and being in situations that just didn't happen, and the real person will have to live with the fact that people who have only watched a film will think he is someone he's not, which has got to be very tough.
Anyway thats enough of a rant about Hollywood changing facts to fit a narrative they want to tell, regardless of the effects of the real people involved