Captain America: The First Avenger

Essential, and the best of the Phase One origin films. It is also the one the chronological order puts near the front, which is defensible here in a way it is not for Captain Marvel: it is set in 1943 and nothing in it depends on anything else.

What makes it work is that the first forty minutes are about a man who cannot do anything. Steve Rogers is physically incapable, repeatedly rejected, and the film's whole argument is made by an officer throwing a dummy grenade into a yard to see who jumps on it. The serum is explicitly not the point and a scientist says so out loud before he dies.

Joe Johnston directs it as a 1940s adventure serial, with a propaganda tour, a stage show, a USO troupe and a montage of raids cut like newsreel, and the period styling is the most distinctive look Marvel had produced. Hugo Weaving's Red Skull is thin and Hayley Atwell's Peggy Carter is the best supporting character in the phase.

The last twenty minutes compress a war into a montage and then crash a plane into ice, which is abrupt. The relationship with Bucky is doing quiet work that pays off enormously three films later.