first Captain America movie was easily the best of the Marvel lot up to that point in time (pre-Avengers).
In many ways, The Winter Soldier is like "The Avengers 1.5." The big Marvel heroes that get to carry their own movies aren't in residence, but Black Widow and Nick Fury are -- and both integral parts of the story. Maria Hill is back too, plus room is made for a new quasi-Avenger in Sam Wilson (minor spoiler: aka Falcon).
What's more, the plot of the film feels much more part of a larger universe than the other quite stand-alone post-Avengers movies have been. It's perhaps a bit overly convoluted in the way it contorts to bring in elements from so many different places, but it's interesting all the same. The short version: Captain America must go up against a possible corruption within the S.H.I.E.L.D. organization itself, and against the powerful hitman employed by the corrupting force.
This movie is easily the most realistic of the Marvel canon. There are still plenty of outrageous superhero antics, but the plot is that of a much more grounded spy thriller, and the themes of the film much more based in reality. The Winter Soldier touches on such heady stuff as freedom, the price of security, post traumatic stress disorder in veterans, Alzheimer's disease, and more. In most cases, it isn't just paying lip service to these themes either; the movie actually has some commentary to offer. This makes The Winter Soldier a fascinating contrast to the earlier Captain America film. The First Avenger was a retro movie with a fun 40s, Rocketeer kind of vibe. The Winter Soldier feels very current and topical.
Of course, movies like this are expected to deliver the action goods first and foremost, and there it also does very well. There are several cleverly conceived action sequences throughout the film, and each has a different tone. I particularly enjoyed the film's opening, a short of "stealth shooter," infiltration sequence. But in any case, you'll get everything from car chases to fist fights to shootouts to a massive finale in the skies above Washington D.C. In short, it's well modulated action, not all one thing.
As Steve Rogers, Chris Evans remains one of the most relatable of the Avengers, a hero who's very easy to root for. But just as enjoyable here is Scarlet Johansson as Black Widow. Her character is woven very well into this plot, not at all tacked on as she was in Iron Man 2, and with a lot more to do than the crowded Avengers could afford her. Black Widow shouldn't have to keep auditioning for her own movie, but if that's what this is, it's a good audition. Anthony Mackie does a good job of establishing Sam Wilson as a real character before the fantastic elements of his story kick in. And of course, Samuel Jackson and Cobie Smulders both kick some ass. (Though it might be that the best performance in the movie comes from the bit player who appears in one scene as an Apple Store employee. He certainly got the biggest laugh from the audience of the entire film.)
But there are a few flaws. The pacing is a bit lax at times, particularly through the middle of the film. It's commendable that they wrote some grounding character moments into the movie, but the plot is generally too dense to make room for them comfortably. And, as always with these Marvel films, the villains just aren't that interesting. (Loki excepted.) There's supposed to be a question of who to trust in play here, but Robert Redford's virtual mustache twirling never leaves you in any doubt where he's concerned. As for The Winter Soldier? Well, he does give us some great action sequences, but the film also seems to be hanging a lot of weight on the "shocking" reveal of his identity, when it's so apparent I don't even feel compelled to issue any kind of spoiler alert.
Still, Captain America: The Winter Soldier has enough going for it to claim the top spot on my list of Marvel stand-alones. I still think The Avengers had just a little more secret sauce, but otherwise this movie is pretty good. I give it a B+.