The Combine Charger (also known as Wallhammer in Combine phraseology) and also called Combine Heavy by players is one of the four Overwatch Commando units deployed throughout City 17 in Half-Life: Alyx.
The Combine Charger are much larger compared to other units. They are distinguishable by their heavy padding giving them a more sizable look. A teal combine emblem is painted onto the right shoulder pad of the armor. Along with their armor, they also come equipped with a shotgun and a shield.
The Combine Charger usually tries to rush the player out in the open. When shot, they will bring up a shield and keep rushing the player. During this period, they are unable to return fire to the player. After a few moments, they will bring down the shield. If they get close to the player while their shield is up, they are capable of emitting a bright flash from their shield, briefly blinding Alyx.
A good strategy for killing a Charger is chucking a grenade behind the Charger while their shield is up. Because of their slow speed, the charger will struggle to evade the grenade. Once they put their shield down, finish them off with the shotgun or pulse SMG.
The Combine Charger has scrapped animations of a different attack.
Said animations saw the Charger switching from their shotgun to their stun baton. After pulling out their baton, they would charge Alyx and hit her with it. No official source has specified exactly why this attack was scrapped, though it may stem from Valve's decision to not pursue melee combat in Alyx.
The Combine Charger serves a similar purpose to the Shotgun Soldier from Half-Life 2, with both acting as flank enemies that put pressure on the player. There is also a placeholder model in the game's files of the Shotgun Soldier.