Here's the fourth video of The Last of Us Development series look at the gameplay mechanics of the game. This episode discusses the "action and potential consequences of inertia".
There are two more episodes planned for release in this series with the first discussing Joel and Ellie, and the fourth final video discussing the games art and music.
The Last of Us was released June 14, 2013 exclusively for the PlayStation 3. Be sure to check out our The Last of Us game section for some helpful tips for playing the game.