They did crazy plot gymnastics. To be clear, the reason why Civil War didn't work as a plot (I realize that they're one of the best selling events and a lot of people like them) in the comics is because too many characters were forced to play roles that didn't suit them. This didn't have as much of an issue with that, and we had Black Widow playing audience with her constant 'wtf are you idiots doing'.
The camerawork stayed out of the way (neither a good or bad thing, just a thing), the choreography was great, and the acting was competent. Bruhl was as great as he is in everything. Rudd, Mackie, and Holland handled the comedy well. Rhodes could've had issues, but Cheadle pulled it off. Boseman and Renner gave their roles appropriate character. I was delighted by the domestic portrayal of Vision, since the current Vision comics are some of the best examples of the medium and genre.
The score lacked something, though.
I don't know why they didn't cast Olsen as Jessica Drew and give Scarlet Witch, if they had to have her, to, say, Isolda Dychauk. I do wonder how they're going to handle robosexuality.
Actually, that sums up the whole movie. It should've been a wreck. We should've had some Bryan Singer-esque guffaws, but they pulled it off. I'm firmly behind the Russo brothers, now. I mean, I loved Arrested Development and Community, but what the hell, they made a movie with a ridiculous amount of corporate entanglement and dozens of different branding interests work.