Heart Of Darkness was actually the first audiobook I listened to. Heard it was the inspiration for Apocalypse Now, so that's how I came across it. I'd put it on before bed and I'd fall asleep to it. I don't really remember much of it now (tends to happen when you listen to shit prior to sleeping), but I can recall some scenes. I reckon I wanna grab a physical copy sometime and read it.

I'm currently listening to Blood Meridian by Cormac McCarthy. Classic book, they say. Only half a dozen chapters in atm, but it feels very Heart Of Darkness-ey. Follows a nameless protagonist through his bloody journeys across America and Mexico during the mid 1800s. Very dark, very intriguing, very well written. Consider giving it a go after you finish Heart Of Darkness - I bet you'd like it.