Don't watch the dramatized version of what happened, as this is the original documentary based off the book of the NFL's coverup of head injuries.
Note I don't say concussion, as that term is very misleading to the actual scope of the problem: It is about repeated blows to the head instead. Hence, the main premise of why I have such a problem with the Disney movie.
Instead this documentary follows the path of NYT and ESPN reporting, and also books "Head Games" and "Brain Game", which would have been the best title for this decades long investigation and cover up, incorporating all of these perspectives into the documentary. Even the NFL, to their credit, had their representatives interviewed here.
I thought this did a good job of covering from the beginning what happened to Mike Webster, all the way to Junior Seau's death and the current state of the NFL at the time of release. It is a long documentary, but worth the time to see how potentially damaging this game is to youth, specifically if injuries and bad techniques are prevalent.