One of the first-revealed deleted scenes was a short, painful conversation between Natasha and Fury about his decision not to bring her in on his survival plan. Scarlett Johansson suggested it be cut because it disrupted the momentum of the film, and the basic gist of the scene is still conveyed without being needed to spell it out. This scene also introduces the photo-veil, the high tech mask that allow Natasha to impersonate the female councilwoman and enter the Triskelion.
One scene reveals a pragmatic reason why Steve ditches the SHIELD version of the Captain America uniform, even towards the final confrontation (putting aside the symbolic reasons for using the WWII outfit). After he escapes the assassination attempt in the Triskelion, SHIELD is able to track his location through a tracker installed in the suit. However, Steve appeared to know about it, and leaves it behind at a public gym for a set of sweats. The STRIKE team comes across it stuffed in someone's duffel bag.
Another deleted scene was one of Maria Hill and Sitwell conversing after Cap's escape, ending with her being put under investigation because of her mild taunt that Captain America tends to inspire loyalty.
The dialogue between Pierce and Natasha about potentially leaking her past alongside the entire SHIELD database ran longer, with a mention that Pierce isn't doing anything to stop it because HYDRA's existence being known to the public won't matter once the Helicarriers are fully operational.
A deleted scene that wasn't filmed was one of Hawkeye being sent to hunt down Steve, catching up to him and the two of them fighting. Steve wins, but finds Hawkeye whispering to him to make his defeat look real, revealing Hawkeye deliberately lost because of a Quinjet recording the whole thing overhead. He also alerts Steve about the tracking device in his suit.
Doing It for the Art: Robert Redford stated that he wanted to do the film because he wanted to experience the new style of film-making that utilised high technology to bring its characters to life.
And the narrator of the Smithsonian's Captain America Exhibit is Gary Sinise, best known for playing Lt. Dan.
The SHIELD Helicarrier launch tech that Rumlow threatens is Desna.
Late-Arrival Spoiler/It Was His Sled: Given that the identity of the Winter Soldier is so well known, marketing makes no attempt to hide it. The film isn't especially careful about concealing the Soldier's identity from the audience either (after he loses his goggles and mask he doesn't replace them). The primary emotional beats come not from his identity being revealed to us, but to Steve.
The poster art keeps the Winter Soldier's mask on; the home release box art leaves him unmasked both on the front and the back panels.
The Russo brothers are predominately directors of comedy, particularly episodes of cult favorites Community and Arrested Development, and aren't exactly the obvious first choice to direct a superhero movie.
Robert Redford joining a superhero film is not the kind of thing one would generally expect from him. He also uncharacteristically plays the villain of the film. Heck, the directors have commented that, in an earlier age, the idea of Redford playing Captain America himself would not have been all that far-fetched.
The directors' commentary notes that the style of the movie was inspired by 70's political thrillers, even referring to Redford's Three Days Of The Condor, who was the protagonist. In a way, The Winter Soldier is Redford redoing the movie as the guy running a conspiracy instead of the agent being hunted, making this also an example of Playing with Character Type
Production Posse: Danny Pudi, who stars in the Russo brothers-directed Community, cameos as a SHIELD technician. The firm who did all the openings for the Russos' shows was responsible for the end credits. Alison Brie was also in the mix to play Agent 13.
Promoted Fanboy: Anthony Mackie is a huge fan of the Falcon, and has gushed multiple times about how lucky he's been to get the role. He even expressed disappointment that his costume wasn't the character's classic red and white spandex.
It's also heartwarming that one of the things he was emphatic about when joining the project was that he was playing Marvel's first African-American superhero.
Anthony Mackie did the film so that his son and other African American children can see that there are superheroes who look like them.
Robert Redford said that the first thing that got him interested in the film was that his grandkids liked the movies a lot.
Stunt Casting: Batroc's moves are pretty convincing - and that's probably because he's George St. Pierre, one of the most respected names in MMA, three time welterweight champion of the UFC, and one of the top ranked fighters in the world, like ever.
Audiences get their first look at Aaron Taylor-Johnson and Elizabeth Olsen as the MCU's Quicksilver and Scarlet Witch; they're the co-leads as husband and wife in Godzilla (2014), opening one month after Cap.
Torch the Franchise and Run: The movie has a rare case enforced by the higher-ups: once the writers expressed interest in a conspiracy thriller, the president of Marvel Studios suggested them to take down SHIELD and have it fight Cap. (while a SHIELD-focused spin-off was running, no less!)
Joe Russo: What it was going to be, we were trying to complicate the relationship between Cap and his S.H.I.E.L.D agent friends. If Hawkeye got a call from S.H.I.E.L.D saying Captain America is a fugitive, would he listen to that call or not listen to that call? That sequence actually was heartbreaking for us to cut it. I think it ultimately might have been a conflict with Rennerís schedule. But there was a great sequence where Hawkeye was chasing Cap through Washington D.C. there was an awesome sequence where they confronted each other in a ravine on the outskirts of D.C. and Hawkeye was shooting a series of arrows closing in on Cap, Cap closing in on him. And then Cap took him down and he realized for the first time that Hawkeye was trying to trick S.H.I.E.L.D, where he whispered something into Capís ear that Cap had a tracker on his suit and to punch Hawkeye to make it look real, because there was a Quinjet hovering above where they were watching the feedback back at S.H.I.E.L.D.