It has been a while since I saw this documentary, so some things might not be completely correct. I will give it a go anyway.
What makes this documentary so great, is that it really captures all important moments of his career, from the very beginning to almost the very end. It is not focussed on Avicii's music, but rather on his mind and the people around him. You see how the people he spends the most time with, are trying to exploit him for personal gain and Tim not being able to tell them no. Now please don't get the wrong idea when I say this, but the fact that this documentary has been released before Tim's death, makes it that much more powerfull. It has not been made with the specific purpose of trying to show why Tim has ended his own life, but rather to show how tough his life IS as an artist and him taking his own life after the release of this documentary only makes this statement that much more powerfull. Yet again, I say this with the outmost respect and in no way mean anything bad by it.
After seeing this film, I feel like I got to know Tim. I encourage anyone to see this, as it truly captures some of his highest highs and lowest lows of a persons life!