Costume

The antagonists and the protagonists wear different clothing. The antagonists wear primarily black clothing. This Immediately tells the audience that this is the bad guy as the colour black connotes evil and darkness. They also wear balaclavas. These are often used by terrorists and criminals in films, as they don't want to give their identity away. Because of this they are usually used to represent bad people.
The protagonists are wearing khaki. This is because the army wear khaki. so it is often used to connote that the people are good and normally professionals. This also gives a sharp distinction between the two groups of people in the film. One of the protagonists has a backsack. This makes him look prepared, therefore he looks like a professional.