There's 5 parts of the documentary.
Level One: birth of video games, talks about classic arcade games like Pong and Space Invaders, and Atari
Level Two: stories, emotion, and recognizable characters are introduced, video game icons like Zelda, Mario, and Sonic appear
Level Three: games go 3-D, first person shooters appear
Level Four: simulation games appear, giving players control, and talks about how Red VS Blue came to be
Level Five: the newest genre of video games, PC games, appear, and the future of video games is discussed
This is from memory so I might have left something out, or made a mistake.