There are several new additions in Episode Two.
 

Characters

Doctor Arne Magnusson
		A former researcher and surviour of Black Mesa, doctor Magnusson is the new addition to the cast of Half-Life 2. He used to be part of the Anomalous Materials research team and compete with doctor Isaac Kleiner for grants, but after the incident (preceded by the ominous loss of his microwave casserole caused by a young researcher) and the Seven Hour War he became one of the key players in the struggle against the Combine oppression. He has a very strict and uptight manner of speaking and interacting with his fellow humans, loathing incompetence and any distractions that prevent him from continuing his work. His single minded pursuit of knowledge (and it's practical application against the Combine) has earned him respect from the Vortigaunts, to the point of them taking over several of his mannerisms. In the end, he appears as an arrogant, insensitive genius on par with Eli Vance and Isaac Kleiner. Yet despite his character flaws, he is the key to preventing another Seven Hour War, which this time, will not last seven minutes.
The Garden Gnome
		This mysterious character, who never utters a word and always maintains a straight face has a dream, a dream only Gordon can help him fulfill and reach the stars.

Weapons

 

Magnusson Device / Strider Buster
		An ingenious creation of doctor Arni Magnusson, a former Black Mesa researcher, the strider buster (or as it's creator prefers to call it, Magnusson Device) is the Resistance's ace-in-the-hole weapon against Combine Striders. Roughly the size of a watermelon, when launched at the Strider's main body with the gravity gun, it draws energy from the walker, allowing any resistance fighter to destroy the synth just by shooting it with any firearm, resulting in an explosion and the Strider's timely demise. The device has also another unique feature, as it's the only piece of equipment Gordon Freeman will have at his disposal, that is provided through numerous dispensers that teleport the device straight from the store room inside the safe White Forest base.

 

Enemies

 

Hunter
		A completely new enemy, the Hunter is a melee-oriented organism created by the Combine, able to withstand massive firepower, with extreme strength in melee and an integrated flechette cannon at its disposal, it will prove to be an extremely deadly and lethal opponent for Gordon and Alyx.
Worker Antlion
		Previously unseen, the worker antlion is one of the new additions to the roster of obstacles Gordon will have to overcome in Episode 2, and not the least deadly, not by far. The worker produces extremely corrosive acid in its bowels and unlike its brethren prefers to stay at a range and "spit" acid at anyone it considers an enemy, inflicting massive damage against anything it touches. In the antlion society, it is solely responsible for carving out their massive networks of tunnels with the aforementioned acid as well as numerous other tasks.
Antlion Grub
		The first stage in an antlion's life cycle, the grub is defenceless and harmless, living in the massive antlion tunnels until it matures and becomes a fully-formed antlion. Until then, it remains underground and feasts on numerous corpses brought to the hive by other antlions. The grubs are an important addition to Episode 2, as their inherent glow provides light during the exploration of the maze-like tunnels of the hive as well as healing in the form of secretion they produce and release when crushed.

       

Vehicles

 

Hot Rod
		An American Dream come true amongst the blight of Eastern Europe. Well, part of it. Regardless, the Hotrod is Gordon's new car, after his buggy was lost to the Combine. It is essentially a salvaged Dodge Charger with a powerful engine, good looks and a sturdy bumper for close encounters.