It was an awesome ending to an even more awesome series. Like every single movie in the Mission Impossible series, the plotline is complex. Don't expect to fully follow the movie through the first time you see it. I always watch these movies more than once, because I like that there are no annoying characters. Ethan lives in an intelligent world that we can all only wish we lived in. One confusing thing Mission Impossible movies do is somebody will ask a question about the plan and then edits show a past scene of characters discussing the formation of the plan. Typically, the person who asked is not in the same room as the people making the plan, but is asking about the plan later, after the plan has been formed.
In this movie, a blonde lady asks Ethan whether his friends know what they are getting themselves into, and then we see Ethan's friends discussing the plan. This is happening in another place, and likely not at the same time, but the edits might confuse you into thinking they are all discussing the plan together, when actually Ethan is alone in explaining that his friends know the danger they face. Anyway, it helps to have seen the previous movies, but I truly enjoyed this movie, just as I did the others.