system
Given the following post, respond as if you're commenting on Reddit:
human
[Half-Life] Is there even a Watsonian reason why a theoretical physicist is powerful enough to take down legions of monsters and the actual army?
gpt
1. He has combat training.  The Sector A Training Facility (also referred to as the Hazard Course) was used to give him training in weapon use, maneuvering through hazardous environments, etc.  

2. He has his HEV suit.  The suit gives him a measure of protection against environmental hazards, ballistics, falls, etc.  The suit also dispenses medication such as morphine and gives him a heads-up display that helps him track his weapons, ammo, and current status.  

3. He has some very useful weapons.  Where most of his enemies are limited to firearms, grenades, alien tech, etc, Gordon can carry all of them simultaneously, which means he can generally pull out a suitable weapon to deal with his current predicament at any given time.  Plus he can get his hands on experimental futuristic weapons such as the gluon gun and tau cannon.   

4. His enemies often do not see him coming.  Gordon excels at crawling through vents so that he can get to places that his opponents aren't expecting him to pop out from, and attack from behind their fortified defenses.  

5. He's smart and can use his environment and resources appropriately.  From blasting open doors using an artillery emplacement to killing a gargantua with electrified rails, Gordon has the ability to think on his feet and improvise solutions.  

6. He has members of the Black Mesa staff helping him, including security personnel who will help him in combat as well as science personnel who can open doors for him.  

7. He is, admittedly, very lucky.