Turrets serves as one of the main obstacles in the Portal games. Armed with unlimited ammunition and deadly accuracy, they will attempt to kill any player in sight.
General
Sentry Turret
Sentry Turrets appear as miniature tripod robots that appear in both Portal games. They are incapable of independant movement, but they can slide their chassis parts (or 'arms') horizontally to reveal two gatling guns. The center holds their red 'eye', which emits a targeting laser.
When the player is unseen, the turret will appear motionless and its guns hidden. Moving into its angle of sight, however, will cause them to deploy the guns with a voice line before they commence fire. They will continue to fire until the player is dead or moves out of sight. If the latter occurs, the turret will have a brief moment where it will search for the player, after which it will resume its inactive stance.
Turrets can be defeated through a number of means. The most common method is knocking them over, causing them to flail and fire wildly before deactivating. This can be done by picking them up and dropping them, or using any object to push them. Additionally, the Thermal Discouragement Beam or Emancipation Grid can be used to completely destroy them.
=Rocket Turret
The Rocket Turret is a unique enemy in Portal 1. It appears as a personality core outfitted with a rocket launcher. Upon activation, it will slowly lock onto Chell and emit a sound before launching a rocket. It plays a vital role in the battle with GLaDOS.
Appearences
Portal 1
Turrets are introduced to the player in Test Chamber 14. Following this, they will be present through the remaining levels.
Portal 2
Turrets return in the sequel as both an enemy to Chell and the Co-op robots. They appear fairly early in the game. Distinct versions of the turret are introduced, including the Defunct Turret and Animal King Turret.