The film's screenwriters play two S.H.I.E.L.D. interrogators.
Winter Soldier creator Ed Brubaker is one of the scientists attending to the character himself.
Joe Russo, one of the directors for the film, appears as the doctor that treats Natasha and Nick Fury.
Deleted Scene: 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.
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.
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.
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.
Production Posse: Danny Pudi, who stars in the Russo brothers-directed Community, cameos as a SHIELD technician. 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.
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.