You saw the movie. If you're like me, you loved it. But maybe you left the theater wondering what creative liberties CAPTAIN AMERICA: THE FIRST AVENGER took with the comics it used as source material. How about we all grab a seat and hash out some of the key differences?
Needless to say, this discussion's going to have a lot of SPOILERS for the movie. If you complain about learning more than you wanted to know after reading this warning, then you deserve to be thrown into the stockade of your own misery.== TEASER ==
THE RED SKULL AND HYDRA
Herr Johann Schmidt and his army of fanatics are the most significantly-changed characters in this picture. In the comics, the Red Skull’s dark reflection of Captain America is more metaphoric than literal. Like Rogers, he’s a dejected orphan who rises in prominence through the circumstances of World War II. He's picked by Adolph Hitler himself in some twisted PYGMALION-style wager to groom the perfect Nazi out of even the lowliest “little man.” Hitler gives Schmidt the Red Skull mask and identity, then puts him in charge of a terrorist division to bedevil soldiers and civilians throughout Europe. It’s the Skull’s success as a propaganda symbol that inspires the US to create Captain America, even though Schmidt possesses no super human abilities himself. In the movie, however, the Skull serves as an actual prototype of Cap (somewhat like Protocide,) with an injection of an earlier, imperfect sample of Erskine’s Super-Soldier Serum granting him superhuman strength as well as his disfigured face.
HYDRA forms in the years after the war as a cultish continuation of the Nazis’ fascistic agenda and of the terrorism Schmidt spread during his active years. Though the Skull associates himself with the organization later, it’s actually Baron von Strucker who founds it. Of course, divisions eventually form in HYDRA and one of the splinter groups that breaks off from it is AIM, the Advanced Idea Mechanics who develop deadly, outlandish weapons.
For the movie, the Skull's been combined with von Strucker, HYDRA's been combined with AIM and the timing of the cult's founding's been moved up by decades. Schmidt's allegiances have shifted from a loyal right hand man of Hitler’s to a rebellious upstart who deems Germany as much of an enemy as the rest of the world. While AIM synthesizes an omnipotence-granting Cosmic Cube that the Skull acquires in the comics, in the movie, he uses HYDRA to see out his occult obsessions with an Asgardian Tesserect, a magic object that serves as an infinite power generator instead of a device that actualizes thoughts. Interestingly, it’s the Cube that grants HYDRA its advanced weapons while, in the comics, its von Strucker’s discovery of alien technology.
James Buchanan Barnes’ depiction in the movies lays somewhere between his reinterpretation in the first volume of THE ULTIMATES and in the retcons of the recent WINTER SOLDIER storyline. In his earliest conception, lil’ orphan Bucky was an army camp's teenage ward and “mascot” who accidentally discovered Steve Rogers’ secret identity and then blackmailed his way into being Captain America’s sidekick. After a couple years adventuring together, the two met tragic ends while trying to stop the flight of the supervillainous Nazi Baron Zemo’s automated, airborne drone. Bucky was (seemingly) killed by the plane's explosion while Cap was thrown into icy waters that would freeze him for decades.
The WINTER SOLDIER arc brought Steve and Bucky’s ages closer together, and also re-established him as something of a junior commando who got all the covert wet and dirty work done for Cap.
The ULTIMATES re-conceived Bucky as a combat photographer who protected his pal, a frail Steve Rogers, from bullies when they were boys in New York City. He later went on to marry Steve’s fiancé, Gail Richards, when everybody thought Captain America had died in combat. If you’ve seen the movie, you’ll know that "movie Bucky" is a combination of these two versions, only with the added twist of him being a simple enlisted man instead of a mascot or a cameraman.
Cap’s origin up until the point he becomes a super soldier doesn’t different much at all from the comics. The movie even gets down to the detail of an elderly woman being the gate keeper of Project: Rebirth. Things differ a little more once Steve gets big, though. The USO bond salesman bit is an invention and the order of inspiration for Cap's identity changes.
In THE ADVENTURES OF CAPTAIN AMERICA, Cap’s deemed too valuable for field duty and he gets some serious ants in his pants while on the lamb. Instead of hawking war bonds, though, he’s kept undercover as a Gomer Pyle-like doofus at a domestic base. He takes matter into his own hands as a vigilante then by going out on late nite runs to smash domestic saboteurs. After he’s found out by his superiors, they grab his sketchpad (he was an art student) and then the PR people get the inspiration to create the Cap identity from his doodles of superheroes.
THE HOWLING COMMANDOS/THE INVADERS
Well, for one, they’re never actually referred to by any kind of group name in the movie. Joe Johnston might've accidentally mislead a lot of fans when he said that the Invaders would show up for a big portion when he actually meant these joes. Perhaps it was considered for a while to use that name for the Howling Commandos, as they’ve been somewhat combined with the group of proto-Avengers. British officer Montgomery Falsworth is in their ranks, after all, and he’s also known as the costumed super-agent Union Jack (a key member of the Invaders) in the comics.
Whatever they’re called, this group of roughnecks is a more quickly-assembled task force than the tight unit of Army Rangers from the comics. Nick Fury made his debut as their leader but, since he's been greatly re-imagined for the movies, his role has effectively been filled by Cap. Also, for the comprehensive trivia hounds: while Dum Dum Dugan and Gabe Jones have always been members, Jacques Denier and Jim Morita were only ever associates of the Commandos.
In the comics, Carter was an American intelligence officer who assisted the French resistance behind enemy lines under the code name “Agent 13.” Her romance with Cap was limited to their team-ups on the battlefield and he never actually knew her real name before he got frozen at the end of the war. In the movie, Carter's effectively been combined with Cindy Glass, a German double-agent from THE ADVENTURES OF CAPTAIN AMERICA who served as Steve’s minder during Project: Rebirth and eventually became his tragic “first love.” Following all of that, the two notable changes to Carter for the movie are that she’s British now (obviously) and that she’s an active field officer in Col. Phillips’ special unit, which serves as a nascent SHIELD in the same capacity that the "Invaders" are a loose proto-type for the Avengers.