A nebulous definition of "let's play".

To establish let's play as a genre, I first have to describe just what is a let's play. In simplest terms, a let's play is sampling of a video game joined to commentary. It is a combination of the video game itself, whether by film or photography, accompanied by the commentary of the player and their play.

While these two elements are always present, the rest is variable. The format could be in writing accompanied by screenshots, or film accompanied by disembodied voice. The commentary could be live (to the game play) or inserted afterwards. The player could be playing an entire game or merely part (and there are arguments as to if playing only part of a game is still a let's play, which I won't antagonize here). The commentary could be attempting to craft a particular story, or the player could simply be waxing nostalgic on childhood memories. Cheating may be encouraged or vilified. I would go so far as to suggest that the commentary could be silent, if the gameplay allows the player to emote their experience adequately.

The genre in name originated on the Something Awful Forums in 2006, but the activity of playing video games and commenting on them has been going on much longer. I'm sure many people have childhood memories of sitting around watching friends play video games and talking. The activity of recording video game play probably originated in walkthroughs and speed runs, and with the advent of Internet video sharing these became much easier to distribute. My primary source of let's plays is Youtube, which biases my viewing towards films with live commentary.

With such a broad genre involving several media, it's easier to say what is not a let's play. A mere walkthrough is not a let's play, or at best, is a very poor let's play if it includes commentary. A speed run is not a let's play, as these are generally not matched to commentary. A piece of pure fanfiction is not a let's play, as it doesn't actually include elements of gameplay (e.g. screenshots, footage), though a let's play may exaggerate elements to develop a story.

Therefore, a mediocre let's play is simply one that provides average gameplay with commentary on the activity but does not attempt to craft anything greater. A bad let's play is one where either the gameplay or commentary (or both) create a distasteful, unpleasant or boring experience where no one is having fun.

An exemplar let's play is one that joins superior gameplay to fine commentary in order to craft a story where both the player and the viewer/reader is entertained.