It has been a long time I have seen the first one but my main issue with it was that they had to explain a series of eventa to the audience by some flashback where it is explained to Ethan.
Hm? Which flashback? The one where Ethan recollects the past events and realizes Jim Phelps is the traitor?
Yes, I believe it is that. There are a series of events where his team gets killed I believe and he figures it out later in a series of flashbacks. But he really really see what happened in the first place so it was explained to him and then he looked back in his mind and envisioned the missing pieces. But honestly, it has been too long for me to now remember how it exactly happened. I would have to go find the scene again but don't have the ability to do it from here.
I could understand why that scene feels redundantly dragged out and might bother you, but I have to say... I really, really loved the soundtrack playing in the background as he figured it out. It was so haunting, and it sums up Ethan's pain so well as he gradually come to terms with his beloved friend being the murderer of his team (and when you consider that Phelps has been with the cast in the TV series for a long time, this has a much weightier context for both Ethan and M:I fans).