Dog

Dog and his master, Alyx, at the base of the Citadel

Dog (sometimes written as DØg or dØg) is a robot and minor recurring character in the Half-Life 2 series. Eli Vance built Dog to protect his daughter, Alyx Vance, as well as to provide a companion for her when she was young. Originally standing only around four feet high, Alyx has steadily upgraded Dog so that he now stands around ten feet high and possesses incredible strength and power.

Episode Two spoilers present.

In-Game Appearances

Dog plays fetch with his "ball" and Gordon at the Black Mesa East junkyard

Gordon Freeman first meets Dog at the Black Mesa East junkyard, where Alyx has them play a game of fetch with various objects, and teaching him how to use the Gravity Gun at the same time. When the Combine begin their assault on the base, Dog opens the airlock door after it loses power, allowing Alyx and Gordon to get through. When they are separated by falling rubble, Dog opens another steel door for Gordon, allowing him to gain access to Ravenholm.

Following Gordon and Alyx's infiltration of Nova Prospekt Dog makes his way to Dr. Isaac Kleiner's lab in City 17 and greets his master after they are teleported out of Nova Prospekt. While Alyx concentrates on getting Dr. Kleiner out of the city safely, Dog and Gordon go out to fight the Combine. Dog flips over an APC that rams him, destroying it, and then hurls it at a few Combine soldiers, killing them. He then opens a barricade for Gordon, allowing him passage. Dog then grabs on to a Dropship that had just landed, which has difficulty flying away with Dog clutching to him.

Dog is later found just before the Citadel, where according to Barney he is convinced that Alyx is being held. He manages to open another path for Gordon, lifting a Razor Wall and allowing him access to the Citadel.

Dog sees Gordon Freeman buried in the rubble at the beginning of Episode One

Dog makes another appearance at the beginning of Episode One. After finding Gordon Freeman buried in rubble and giving him back the Gravity Gun, he assists Alyx in contacting her father and Dr. Kleiner. He then lifts a crashed Gunship out of the way, allowing Gordon and Alyx a path to an entry point into the Citadel. After estimating the distance from the ledge to the Citadel, he finds an old van, beckons Alyx and Gordon to get in it, and tosses them across the chasm and into the Citadel. Alyx instructs Dog to find her father and get out of the city as soon as possible. Nothing more is seen of Dog for the rest of the Episode.

Dramatic preview poster for Episode Two showing Dog facing off with a Strider

In Episode Two, Dog faces off with a Strider near a shallow creek. He manages to kill the Strider by tearing off its armor and ripping its innards apart, but is almost seriously injured when he is hurled against a rock. However, he is fine, and races Gordon and Alyx to the White Forest base. Dog does not make an appearance in the large battle between Gordon and the Striders. After the launch of the rocket, he manages to save Gordon and Alyx from the Combine Advisors, although he was too late to help Eli Vance.

It is not known if Dog will play a part in Episode Three.

Appearance, Abilities and Personality

Dog is a powerful robot standing around ten feet tall. He seems to be made mostly of scrap metal, with several hydraulic augmentations to give him immense strength. He has what appears to be a salvaged Combine Scanner for a head, but with only three flaps instead of the usual four. He also has a Zero Point Energy Field Manipulator similar to the one Gordon Freeman possesses bolted on his right hand. His movement is similar to that of a gorilla's. He is very well-armored, and appears to be bulletproof and able to take severe punishment, such as being rammed by an APC. He also possesses great agility and speed.

Alyx asks Dog if he "did the math"

Dog has mannerisms and habits much like an actual dog. Like a biological dog, he will bow down and retract his "flaps" when in a submissive and happy mood, much like a biological dog will lower his ears when in the same mood. He is fiercely loyal and very loving to his master, Alyx, and as time goes on moreso towards Gordon as well. Conversely, he can show immense anger and aggression to anything attempting to harm his master and her friends and family; namely, the Combine. He often displays rash behavior at his attempts to destroy the Combine, such as clinging precariously to a Dropship, wholly unconcerned about his well-being. Dog also shows advanced intelligence, and is able to completely understand what is being spoken to him, as well as being able to formulate plans and carry them out.

Trivia

• Dog provides comic relief through his antics, and also gives a sense of security to the player thanks to his loyalty and great power. Because of this, Dog is one of the most popular characters in the game, and VALVe states that they specifically wrote the script of Episode One so that the first thing the player sees would be Dog.
• Dog functions as a deus ex machina in many instances, such as creating new pathways by forcing open Combine gates.
• In Episode One, when Dog shakes his head when Alyx asked if he "did the math", Valve states that during the development process the shaking of the head a pure coincidence when he is asked the question. Playtesters enjoyed it enough to persuade Valve to include it as a scripted animation.
• Dog has no true AI to speak of, as all of his movements and fighting sequences are completely scripted.
• Although it is possible to kill him by spawning him and then attacking him, it is very difficult as he possesses a huge amount of health.
• Dog's in-game entity is npc_dog.
• Valve currently offers a shirt that has Dog's head on the front and the words, "Good Dog" written underneath.