Heart of Darkness is a cinematic platformer that's in the vein of developer predecessor Another World, which is another Eric Chahi cinematic platformer. Andy has the ability to run, jump, walk, climb and do the salto somersault, which lets him hang longer in the air. In addition to this, he can attack or defend by using either a plasma cannon or by throwing magic energy, depending on which section of the game is being played. The game is notable for the number of disturbing ways that Andy can be killed, as with all cinematic platformers. While the deaths of the game's enemies are for the most part visually cartoon-like, Andy himself can be crushed, incinerated, drowned, fall to his death, have his spine broken, or get eaten alive in unnervingly graphic detail. Despite this, the game still retains an E rating.
As an extra gimmick the game came with a pair of red/green 3D glasses so certain scenes could be viewed in 3D.