:Enemies:

Light Military Combine
A new type of combine thats used by the overseers and has authority over breen, their main priority is to watch over Breens operations and report back to the overseers of any suspicious behavior.


Heavy Military Combine

A powerful LMC that has been bio-ingerneared, This guy is the squad leader and can issue orders to his squad. compared to the standard LMC they are taller and have a heavier body build with an advanced combine helm and more armour plats.

Security bot
Security bots (referred to as "Patrollers" by the Combine) are walking turrets. They have four mechanicle legs equiped with shields to defend its head. its top can spin over 360º Due to its armoured legs it make a very destinct noise when walking, which often is a good indicator of one nearby.

A list of some of the existing enemies in Half life 2
City scanner

City scanners, often referred to simply as scanners, are piranha-like, flying security cameras used by the Combine to monitor City 17's citizens. They are equipped with a built-in camera and a blinding searchlight. City scanners have no weapons, but the blinding searchlight and the photographic flash emitted can temporarily blind a person. They are lightly armoured, and can easily be destroyed by launched objects, gunfire, or by simply being smashed with a hard object. When a city scanner receives critical damage, it attempts to crash itself into its attacker in hope of doing damage to him. They are powered by a single Combine battery, and a destroyed unit will occasionally drop such a battery.


Rollermine

Rollermines are electrically charged, spherical devices slightly larger than soccer balls that react to movement within a sizable radius. Rollermines are used as offensive and defensive traps by the Combine. As the name implies, they roll towards enemies in an attempt to electrocute them. Extensively used along the coastal roads, the mines are deployed from the air by Combine dropships, in groups of two to four. Upon landing, the mines will remain inert or, if they land on softer terrain like soil or gravel, they will burrow themselves into the ground, remaining almost invisible. When an enemy target is detected, the roller mine will pop out of hiding and roll towards it in a relatively straight line. They inflict damage to people via close-range electric shocks.


Hopper mine

Hopper mines are anti-personnel proximity mines that hop into the air towards the target before exploding, much like a bouncing betty. These mines are carried and deployed by shield scanners. They are vaguely cone-shaped with three sharp "legs". When dropped, the mines use these legs to bounce around until they land right-ways up on a smooth surface. They then jam the legs into the ground, attaching themselves very firmly.
When an enemy target comes close, the mines light up and give off a warning chirp. If the enemy target gets too close, the mines will toss themselves unpredictably, nearly two meters (six feet) into the air, and explode upon contact with whatever they happen to hit on the way down, which is usually the ground. They also detonate if smashed too violently. Otherwise, they are impervious to nearly all forms of handheld weaponry, save for the gravity gun.


Sentry

Sentries (referred to by the Combine as "sterilizers") are automated gun turrets mounted on a tripod. The Combine sentry shares a similar appearance and function with those used by the fictional Hazardous Environment Combat Unit of the United States military in the original Half-Life. However, the Combine version does not use secondary laser "tripwire" detectors, using motion detection (or optical) sensors instead. The Combine sentry also has a narrower field of view and range of motion, whereas the HECU's turret is able to rotate and fire in nearly any direction.


Turret

Combine turrets are placed in the floor, and unlike sentries, cannot be moved. Turrets will activate if their laser trigger is disturbed. They will spring up and begin firing at anything they consider to be hostile. Turrets have a 45-degree firing arc, which is indicated by two blue lasers emitted from the turret while it's activated. It is very easy to avoid turret-fire by simply staying out of the visible arc. While the turret is activated and idle, it emits a repetitive beeping sound, and if there are no hostile units in its vicinity, it will deactivate and retract back into the floor.


Mounted pulse gun

Mounted pulse guns are simply stationary pulse rifles just like the ones carried by Combine soldiers but with a different outward appearance (a longer barrel, slightly different shape and color scheme). They can be found many places in Half-Life 2, including the canals, the wasteland, City 17, Nova Prospekt, etc. Soldiers on defensive structures attach mounted pulse guns to a nearby shield wall. Once in place, the gun can be fired by humans and transhumans with a high degree of lethality. Mounted pulse guns have unlimited ammo and an attached flashlight, as well as a targeting laser. The mounted gun is a reliable defense, but any explosive damage to the shield wall that the gun is mounted to will render the gun useless.


Ceiling mounted camera

Seen in many City 17 citizen checkpoints and the Citadel, ceiling mounted cameras are automated machines primarily used to identify individuals based on their appearance, using a built-in camera, and take appropriate action depending on the information gathered from the pictured individual. They have the ability to grant access to an entrance for valid citizens or stalkers, or denying access to entrances for invalid citizens or unidentified individuals, which includes Gordon Freeman, while sounding an alarm and taking several photographs of the individual. Certain cameras may be seen programmed to redirect an invalid individual to an alternate access point or room, where they may be interrogated, or are directed to special destinations.


Apc

Armoured personnel carriers are the main ground vehicle used by both the Combine's Civil Protection and Overwatch forces, for transport as well as for combat. Resembling large armored trucks or vans, Combine APCs are a good example of how Earth-based designs are often adopted by the Combine and re-interpreted with their alien technology.


Hunter-chopper

Incredibly powerful, the hunter-chopper is a combat helicopter used, as the name implies, for search-and-destroy missions against weaker targets. Like the APC, this vehicle is a conventional Earth design (similar to a Mil Mi-24 Hind) co-opted by the Combine and modified using its own technologies. It utilizes a two-man crew of Overwatch soldiers; one pilot and one gunner. The hunter-chopper is armed with a powerful pulse turret on a fixed mount and has the ability to drop explosive timed mines. The gun has a wide spread and is used mainly on slow or stationary targets. Before firing the hunter-chopper emits an audible "whining" sound that can be used as an indication of when the gun is charging up. The hunter-chopper also has the ability to launch a barrage of "dumb" rockets, though this is seen only once in the game, towards the end of the Black Mesa East chapter. If the player remains in the base's scrapyard after the scanners and headcrab shells arrive, a hunter-chopper enters the area and barrages a sewer-hole opening with these rockets.