Idris Elba stars as the charismatic and brutal leader of an African child army, who wages a campaign of terror on a local government, reported Rolling Stone magazine.
"Beasts of No Nation" is told through the eyes of a young boy named Agu (Abraham Attah), who is drafted into the militia when his parents are murdered.
Fukunaga shot the feature film on location in Eastern Ghana last summer as part of a global deal with Netflix.
Netflix marks its official foray into feature filmmaking with the debut of "Beasts of No Nation" on October 16.
"Beasts of No Nation" is an adaptation of Uzodinma Iweala's 2005 novel, and boasts a score by former Red Hot Chili Peppers drummer Cliff Martinez.