I am a big fan of Half life series, I know many facts, theories and general things. Well… I just can’t say one thing for sure. Overwatch is a Universal Union’s force on Earth but okay. Is the appellative Combine related just to Overwatch or the whole Universal Union?
Um… what? You might want to rephrase that question.
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Combine = Universal Union (they are the same thing)
Overwatch = Name for the Combine’s military forces on earth
They also have an “airwatch”, I think, and the Civil Protection are a lesser police force. When a CP distinguishes themself, they get shipped off somewhere to be gutted and turned into a post-human, cyborg Overwatch Soldier.
Ok… But CP’s count to overwatch, airwatch also.
Magnusson mentioned “Combine Overworld” in episode 2 so I think it’s the name of the whole organization.
No, Civil Protection officers are unmodified humans, and a lesser division of the Combine’s human ranks.
Well, it’s possible that “Combine” is a specific race or races within the “Universal Union”, specifically tasked with taking over/enslaving/pillaging planets.
Well, doesn’t the use of the term combine itself imply that it’s a combination of races?
The emPHAsis is on the wrong syLABble for that. The word is closer to a piece of farm equipment and could be the nickname given because a combine (farm equipment) harvests grain and such by cutting it down and packing it for shipment.
It’s possible that the Combine (HL2) did something similar (harvesting humans) in “the First Days” (as Alyx calls it in Ep2).
I think they pronounce it the way they do in game because saying it as the verb “combine” sounds funny. It is the name of the alien race, so they pronounce it as the noun “combine”. I was under the impression that they were named that because when they invade worlds, they “combine” the technology of the native occupants with their own tech, eg. the Overwatch are cybernetically modified humans, and they use some weapons with combusting ammunition like humans used before the invasion, among other things. Even the locks they put on many of the doors you come across in the game are a combination of human tech (door) and combine tech (lock), instead of just replacing everything.
Honestly, the way the Combine combine alien and normal stuff is probably due more to Viktor Anatov’s (spelling) personal style than anything else. Ever played Dishonored?
True enough, but the art style still fits the story. Or rather, the story fits the art style 
Viktor Antonov better make something new when he does the concept art for another game, or I will lose respect for his (un)creativity.