First, it looks like the following movies won't be made:
Guardians of the Galaxy 3
Doctor Strange 2
Black Panther 2
The Avengers (whatever movie might be next)
Thanos, I am sure a lot of people look at him and see a villain, but me, I see a god. If you believe in a higher power isn't Thanos just acting as the god from the Bible did when he destroyed Sodom and Gomorrah or flooded the earth, only saving one single family group. Thanos does go about what he is doing wrong, by destroying have of all universes he is also destroying the good in life.
This was not the best movie ever, and a lot of the judgements the characters made seemed to fulfill one purpose, help Thanos win. Throughout the movie I don't think anyone was surprised as each infinity stone was retrieved by Thanos. I think the only thing that might have been a surprise was the amount of main characters who were killed or died in the events leading up to Thanos getting the infinity stones.
In the end this was a very long (two and a half hours) trailer for the next movie, which seems to be a revenge story with an added mystery per the end credit scene.
Back to this movie. The acting was okay, but since there was so much going on there was almost too much to pay attention to. The things that would have been funny in other movies were lost in the mass of things that were happening in this movie. Thor had a few funny moments, as did The Hulk, but neither had enough screen time to be appreciated. It was the same with the characters from Guardians of the Galaxy. As soon as Thor was pulled into the ship he made jokes, and the others made jokes, but then the movie jumped to a different scene. A lot of what the characters did was frustrating. They had several moments when they could have saved life on all planets, but instead they reacted badly and waited too long to react, which doomed not only beings we have and will never meet, but also some very well-loved characters.
For example, when Gomorrah dies, as a participant in the audience I was angry that she chose the life of one person over the life of many. Then not only does she take Thanos to the place where she hid an infinity stone, but she tries to sacrifice herself too late to be of any good. If she wanted to help life and save a large number of life on all planets, she would have sacrificed her soon as Thanos had captured her, not after having a father/daughter talk with him. This wasn't the only time in the movie that felt unnecessary.
Later, towards the end of the movie Vision and the Scarlett Witch have a decision to make, and it is one they should have made a lot earlier in the movie, then maybe Thanos wouldn't have killed them both and life in all other universes would have continued on, not knowing that there had even been a chance of their untimely deaths. I understand that the love story between the Scarlett Witch and Vision had to be explored a little more, but it didn't add anything to the movie, and it really made everything seem long and as if there wasn't any point.
I think that was the problem. In the end I thought this was one of those movies that didn't need to be made. Couldn't the next movie have started with the end of this, Thanos getting all of the infinity stones and killing as much life as possible? Another issue I had was, if Thanos was doing all of this to eliminate half of all other worlds to help them, then why did people like Mantis have to die? She was the last of her people, at least that was what she said in the last GUARDIANS OF THE GALAXY movie. She isn't the only one who I questioned the death of, especially since she was not the only character who was the last of her species. Several of the deaths seemed pointless, which often seems true for deaths, but when the Black Panther faded away I wondered why they would choose to do that when the BLACK PANTHER movie made so much money.
This might just be the fatalist in me, as the person I saw the movie with said that maybe everyone wasn't dead and this is going to turn into some time shift or alternate universe timeline device, but for me, I am not sure. If these characters are actually dead the Marvel universe has killed some very beloved characters and left behind characters that may not be able to hold things up on their own.
After saying all of this, I will say I did enjoy this movie. I enjoyed the interaction between some of the characters, but there wasn't enough to keep me from being frustrated in the fact that people were going to die, or that this movie was a very long trailer for something else. I don't appreciate movies that take place just to fill space, and this was how I felt about ROGUE ONE. It wasn't a bad movie, but it wasn't necessary.