Heart of Darkness
Heart of Darkness (1899) is a novella by Polish-English novelist Joseph Conrad about a narrated voyage up the Congo River into the Congo Free State in the so-called "heart of Africa". Charles Marlow, the narrator, tells his story to friends aboard a boat anchored on the River Thames. This setting provides the frame for Marlow's story of his obsession with the ivory trader Kurtz, which enables Conrad to create a parallel between what Conrad calls "the greatest town on earth", London, and Africa as places of darkness.
Heart of Darkness (video game)
After traveling across the varying alien environments and fighting alongside the Amigos, Andy finds himself inside the Master of Darkness' lair where he proceeds to free Whisky and join forces with the Vicious Servant to help overthrow the Master of Darkness. Planning to use the magic rock's power to destroy the black hole at the lair's center. However, Andy is double-crossed by the servant who kicks Whisky into the black hole and sends Andy into an ambush. Andy ends up fending off droves of shadow creatures and successfully following through with his plan, but falls into the black hole himself along with the Master of Darkness as the structure around him collapses. 
The black hole's center is the heart of darkness and there Andy must fight the Master and face his fears once and for all. Upon succeeding the darkness dissipates and Andy awakens in his treehouse, believing the experience was all just a dream but after Andy and Whisky go to sleep and it's shown Andy has likely gotten over his fear of the dark, the player is shown the Amigos cleaning up the wreckage of Andy's ship and proving the adventure was perhaps more than imaginary.