No spoilers, at least no worse than anything you’ve already seen in the trailers.
1) This should have been titled “Avengers 2.5: Civil War.”
2) Tony Stark really, really needs to seek professional psychological help for his issues.
3) Ant-man gets no respect.
4) The answer to Black Widow’s question to Tony Stark is, “No, no he can’t.”
5) The villain problem is circumvented by pretty much eliminating the need for a villain in the first place.
6) While an admirable effort to fit in, the Vision really should not try to wear normal clothes. It just looks weird.
7) The ordinary citizens of the MCU are really ungrateful.
8) Marvel Studios gets Spider-man.
9) The credit teaser in Ant-man is actually a scene lifted from this movie.
10) If you are an ex-secret agent, for goodness sake don’t take any of the incriminating documentation with you when you retire/defect. Especially if you defect.
I liked the movie quite a lot. It’s pretty good and one of the best of the MCU movies especially for having to feature so many characters. For those who don’t want to watch all the movies, the only necessary precursor is really Captain America: Winter Soldier. This movie helpfully provides a recap of the Avengers‘ past adventures (which leads into point number 7 above). Also, just know that pretty much everything that’s happened is Tony Stark’s fault. Heck, I may turn that into its own musing.