The Dogs of War (1980)

It's not until the last quarter of the film that it even begins to resemble the explosive-looking MGM cover art. Prior to that happening it's a tense drama in which a mercenary (Christopher Walken) posing as an ornithologist goes on a dangerous reconnaissance mission to Africa in 1980.
The script (based on a 1974 novel of the same name by Frederick Forsyth that I've not read), the director and Walken himself do a tremendous job characterising the protagonist without taking the focus away from the seriousness of the situation unfolding around him. Likewise, the actor manages to convince us that he's both affected by and distanced from the aura of oppression that fuels every African scene; i.e. while convincing the authorities of disinterest, he allows us to perceive the weight on his soul.

3½ leaky barrels out 5

NOTE: version reviewed is the 118 min UK edition. The US edition is cut.