The movie is simple and well-acted but I have a pretty big gripe about it. Warning, big spoilers ahead.
The majority of this movie is his life after his wife and daughter die in a forest fire, possibly in their home he was trying to get back to. Him questioning whether he could have saved them had he done anything different in his life. I'm sorry but as a father I'm completely out on these types of movies. The very beginning of First Man has Gosling sitting by his daughter's crib who is dying of cancer and he's just waiting for the inevitable, maybe the most gut-wrenching stuff I've ever seen as a parent. I just cannot get to a place where a story with kids, especially young ones, dying is something I can appreciate regardless of the acting, story, or how visually striking the movie is. Joel Edgerton is literally sleeping in the ashes of his burned down home where he wife and daughter likely died. He waits for them to come home for years, they never do. I also didn't understand what was happening with the young woman who ended up in his home with a broken leg who is just gone the next morning and whether it was just his imagination. He understandably never gets over this loss the rest of his life but somehow has some sort of epiphany or sense of appreciation when he's riding in an airplane for the first time? I doubt that man would do anything other than be sad for the rest of his life and if they're trying to express something more profound than that it was lost on me. This movie just makes me mad thinking about what I watched this weekend. Had I known what was going to happen in this movie I would have watched something else.
I'm not trying to invalidate your enjoyment of the film, I'm glad you did like it. I'm sure others will as well but this is just about the definition of a movie I can't get behind. I know this was based on a novel or novella so there's source material but I was not familiar with it.