This movie is a mixed bag for me. It is not a good nor is it bad. It is Meh.
Pros; Pretty Visuals and settings. A decent plot. The main villain has an interesting motivation, although poor execution in terms of character arc. Thor and Val and Rock man are still likeable characters.
Cons: The movie is not very funny. Some jokes hit, but most don't. This movie tries too hard to be funny to the point it is just underwhelming. The movie also falls short on emotional impact. The serious scenes are too abrupt and flat to care about.
Though the concepts of the story are interesting, the writing doesn't do it justice.
Chris Hemsworth's acting is wasted in this film.
The dialogue and exposition is just too much. Too blatant and uninteresting. Nothing is subtle.
I wished the Guardians would still stick with Thor. It would have been much more intriguing story if it was about Thor and the Guardians being a unit and growing together. But nope.
So here's my biggest gripes; the romance. Dear God, it is terrible. The romance in this movie is forced and just plain cringe. Granted; I am not an romantic, but I would have preferred the romance subplot to be miminal and subtle just enough to both make a meaningful impact on the story and characters and not override the plot. The chemistry between the two main actors just isn't there. Thor has more chemistry with Quill than Jane.
Speaking of which; Jane is my next biggest gripe. I can't stand Jane. I just couldn't. I watched the previous Thor movies and I remembered that I did not care for her. This movie didn't change my perspective. Well actually it did; but not in a positive sense. I was indifferent to her almost halfway through the movie, until the middle when the group is in the hospital and it is revealed that the Hammer is preventing Jane from healing properly. Jane, despite being established as this logical and analytical person, insists that she keeps fighting despite the emotional pleas from Thor and even has the audacity to insult Thor about his judgment. She comes back to the battlefield with no consideration of the pain she's putting Thor through and just saves the day because she does. And then dies.
(Also one plot hole I didn't understand; why didn't Thor take his Hammer from the hospital? He could have had the Bolt and the Hammer together.)
Anyway I understand Jane wanted to fight for honor, but I personally do not like when characters who are in awful shape, chooses to go fight because their declining health impedes the mission. Jane is portrayed as heroic, but really she's just plain selfish, and risked not just her own life, but everyone around her including Thor and the children.
Not to mention Jane has no true motivation or purpose to even be in the story. She's just there. Her character is just Mary suish and just lacks emotional depth. I did not feel anything when she died.
The child actors can't act.
Overall the plot is dull and underdeveloped, plotholes sprinkled everywhere. The characters are either underused, wasted, incompetent, or poorly written. This movie is not something I watch twice.