Turrets is a video which was released by Valve on April 5, 2011 in order to promote Portal 2. The video takes the form of an Aperture Laboratories investment opportunity video, and uses a combination of Aperture Science's hallmark animations and pre-rendered footage in order to showcase the consumer version of the Aperture Science Sentry Turret.
"Turrets" Video Transcript
|[Aperture Science theme plays as the Aperture logo appears.]
Cave Johnson: Cave Johnson here.
[An animated scene fades in where many turrets are dropped into view and activated.]
Cave Johnson: Introducing the consumer version of our most popular military grade product;
[Turrets chattering: "Hello?". The view zooms past the turrets as another turret fades in.]
Cave Johnson: The Turret.
[The turret is pulled apart in a cutaway, revealing many bullets stored inside.]
Cave Johnson: How do we get so many bullets in 'em? Like this.
[In a diagram on the side, bullets are poured into the middle of the cutaway turret, marked "Shell Redistribution Chamber". The turret parts begin to fall, leaving the side gun mechanism in place. Zoom in to a cutaway of the gun mechanism.]
Cave Johnson: Plus, we fire the whole bullet. That's 65% more bullet, per bullet.
[Cut to a pre-rendered scene. Three turrets guarding a co-op exit activate, and shoot at Atlas and P-body, who run away from the turrets.]
Cave Johnson: This is the same technology we've been using on robots for decades. Scares the hell out of them.
[A display is shown of different turret styles.]
Cave Johnson: They come in hundreds of designer colors including forest, desert,
Turret: I'm different.
Cave Johnson: table, uh, an evening at the improv... what idiot picked these-
[Static cut to a turret assembly machine. The turret retracts its gun arms and legs and is stored into a "Sentry Turret" box.]
Cave Johnson: Then we box 'em up, and ship 'em straight to your doorstep.
[The box falls into an animated diagram of a bedroom in front of a blue sky background. Upon landing, the box packaging breaks open, and the turret unfolds. Two stick figures, representing parents, are shown waving.]
Cave Johnson: So you can protect the things that matter most.
[The scene changes to nighttime, and the turret's red light turns on.]
Turret: Good night.
[The Portal 2 logo appears.]
Cave Johnson: Just try and get close to that baby. Hah! Your funeral. Cave Johnson. We're done here.
- Although Cave Johnson's statement that Turrets "fire the whole bullet" may seem nonsensical, the video demonstrates that they do indeed fire the entire bullet. Instead of striking the primer on the back of the bullet in order to ignite the propellent inside and unleash the bullet similarly to traditional firearms, Turrets fire bullets via a pair of spring-loaded hammers that propel the entire cartridge out of the barrel. This also explains why Turrets don't eject any spent cartridges when firing. However, this does not explain why the in-game turrets have an explosive effect when bullets are shot, as there is no propelling explosion within the turrets.