Marvel has mastered the formula for fun and serviceable superhero films, but despite its scale and ambition, "Avengers: Infinity War" fails to propel itself above middling Marvel fare.

Out of the three main Marvel series, Captain America seemed like it would be the least likely to succeed. While Iron Man and Thor were allowed to roam free in action and sci-fi set pieces, Captain America was rooted as a more realistic character. Ironically, it is this exact realism and darker tone that make “Captain America: The Winter Soldier” the best Marvel film yet.