I didn't get why Stark went and got Spiderman to help him since he was just a kid.
The fights were pretty silly - Iron Man should have easily defeated Cap and Bucky, and I don't get how Cap was able to survive being punched by Iron Man or Bucky since he doesn't have some super forcefield. They would have just destroyed his face or punched right through his chest (OK Iron Man might have tried to avoid that, but Bucky wouldn't, and I doubt Stark is able to make his punches weak enough not to break bones). All those guys Bucky punched would have had broken chests/ribs and probably died from internal bleeding.
The bad guy's plan was so convoluted it was just silly.
Again Ant-man's powers make no sense within the rules of the universe, since Pym's daughter said he was strong because he would be hitting with the strength of a 200lb man through a tiny fist, therefore when he grows he must also have the strength of a 200lb man, so couldn't pick up all that stuff. He atoms are either spread apart or pulled together, there is not supposed to be any change in strength.
This film just reiterates how silly it was for Deadpool to make a big deal about killing people in his movie since The Avengers killed bad guys within the first 10 minutes.