If I had any complaints I'd say the Stan Lee cameo sort of threw me out of the movie a little, not sure if it was because his goofy hamming it up didn't fit with the tone of the movie or what, but I think they could have found a better moment for it. Also, not sure the whole Agent 13 thing was done that well, at the end they show her in the CIA shooting range but it's like, why should the audience care, they didn't reveal to them that she was Sharon Carter, Peggy's niece, let alone tell Steve, so casual observers might ask why they're supposed to care about how the storyline of the neighbor who's secretly a shield agent spy turns out. It was one of those that was a bit too drawn out to just be an easter egg, but not really fleshed out enough to be relevant or necessary to the plot either.
Anyway, that mid-credits Twins reveal was outstanding, as were the initial silhouette credits themselves. Also, I read that the little to-do list Rogers has where he notes Marvin Gaye at the beginning is a little different for every country, for example down here it had Tim Tams and AC/DC on the list. Here's a nifty link to see some of the differences for each country.
https://movies.yahoo.com/blogs/movie-news/what-s-on-captain-america-s-to-do-list-across-the-globe--194542393.html