Overwatch Sniper Rifle

The Overwatch Sniper Rifle is another example of Combine pulse weapon technology. The rifle is used by Overwatch Snipers. It fires powerful pulse rounds and emits a blue beam used much like a laser sight. It is another co-opted Earth design, based on the South African NTW-20 sniper rifle.

Usage
Highly trained Overwatch Snipers use this weapon to great effect, especially in urban areas. The rifle is very accurate and extremely powerful. It emits a blue lasersight to help with aiming, but this tends to give away the sniper's position.

The rifle fires a powerful pulse round capable of destroying a wide variety of targets. These rounds are powerful enough to kill most targets in one shot and send objects flying several meters from the force of the impact. In this way the rifle can be used to limit the target's available cover, by destroying it or simply sending it flying.

Although originally planned to be accessible to the player, this feature was cut during Half-Life 2's development, and in the final game the player never acquires the Overwatch Sniper Rifle, however, his companion, Alyx Vance uses it briefly in both Episode One and Episode Two.

Appearance in Episode Two
During Half-Life 2: Episode Two's third chapter, Freeman Pontifex, the player encounters a mounted sniper rifle firsthand at an abandoned Resistance base. This seems to be the same rifle used by Overwatch Snipers in the previous games, but was never actually seen until now. The rifle appears to be quite bulky, so it may be the case that the sniper rifle must be mounted to be fired effectively. This would also explain why the rifle is never blown out of sniper's nests by grenade blasts along with it's user. It appears to require energy to operate, as your Vortigaunt companion states in Episode Two: "the gun would appear to be powerless", he can then be seen using his abilities to recharge it as you head into the industrial complex. This is also consistent with the electrical "charging" whine it emits between shots. Once charged, it is used by Alyx Vance to cover Gordon as he moves through the complex. Curiously, if a grenade is fired from the SMG (HL2) into the room where Alyx is firing from from by the grenade ammo box after the first swamp section, a burning soldier body falls out, accompanied by the normal static burst noise. This was due to it was easier to reprogram a sniper to be an ally then it was making a new model for Alyx using it.

Trivia
The NTW-20, the real world rifle wich inspired the design of the Sniper Rifle, also influenced the design of the human Sniper Rifle in the Halo series of games.