It is worth noting that vocal stress is placed on the first syllable. The name is pronounced as the noun COM-bine, as in combine harvester, as opposed to the verb form com-BINE, as in “to join together or unite.”

– wikipedia

The most clear sign of the Combine’s effect on the planet is the drop of the sea level after Combine rule. Pictured here is a dry harbor in the Highway 17 chapter of Half-Life 2, evidently depicting the sea much further from port than usual, with large ships resting on what was previously seabed.

The Combine is a vast empire spanning multiple dimensions. The empire is inhabited by an unknown number of sentient, intelligent species, and appears to be governed by a race of bizarre, artificially-evolved Advisors (see below). The Combine expands its empire by invading worlds and enslaving the dominant species to be exploited as it sees fit. By manipulating these inhabitants, through methods including bioengineering and implantation, the Combine creates a race of super-soldiers uniquely adapted for the environment of that particular world. This process results in a highly mobile and adaptive military force which is able to respond to any threat and crush any opposition. The reasons behind the Combine’s imperialism remain unknown throughout the game.

This is an interesting thing I didn’t even think about for HL2. The Combine goes from planet to planet assimilating the residents into their army and soaking up the natural resources of the planet. Like a farm combine, they combine planets’ resources and people into their collection.

The pronunciation has a bit of a double meaning.