Seaside in the district of Songolo there is the Mazra Club, a beach club near a stretch of mangrove. The mangrove ecosystem, the seaside location and the different private "paillottes" make this a comfortable place to hang out. Local beer or "jus" costs you 1000 XAF. Be sure to ask the cab driver if he knows the place, because it's rather hard to find.
Conkouati-Douli National Park
A five hour drive in the dry season North of Pointe Noire, near the Gabonese border is the vast and relatively scarcely visited national park of Conkouati-Douli. Elephants, gorillas and chimpanzees can be seen here. Be sure to strenuously ask your guide to do a tour of the Ngongo river as late as possible and to go down the river with the engine turned off to see elephants and gorillas.