SHARE launched a free videogame as an element in the buildup to the feature film Captain America: The First Avenger, which opens on July 22. The game was created by Big Pixel Studios and has the deliberately retro style that developer is known for, along with a kitsch quality that encourages fans to share it with their friends.

The online game is part of an entire month of related content, including stories about the characters and interviews with the movie’s cast and crew, that are indicative of Marvel Entertainment’s transmedia approach to its intellectual property.

Captain America: Shield of Justice is a simple platform game designed to look like a 16-bit game from the 1980s. Several of the movie’s main characters are in the game, albeit formed from chunky little boxes. It’s certainly not competition to the movie tie-in console game Captain America: Super Soldier from Sega, another expression of Marvel’s characters.

Marvel previously worked with Big Pixel on Thor: Bring the Thunder, another retro platform game that supported the May release of the movie Thor. It also had a console game tie-in from Sega, Thor: God of Thunder.

Marvel Studios already has announced two upcoming feature films that will benefit from the same cross-platform treatment, Marvel’s The Avengers on May 4, 2012, and Iron Man 3 on May 3, 2013.