I haven’t been to Congo yet, but I’ve included community reports from those that have.
Congo – Odzala-Kokoua National Park, 2013: Cheryl Antonucci, 1 week & 22 species including Marsh Mongoose, Beecroft’s Anomalure, African Palm Civet, Hammer Bat, Northern Talapoin, De Brazzas Monkey, Lowland Gorillas and Chimpanzees.
Dzangha Sangha and Nouabalé-Ndoki, 2010: Sjef Ollers, 3 weeks and 23+ species including Lowland Gorilla, Brush-tailed Porcupine and Red River Hog.
The Congos, Cameroon and Gabon, 2009: Vladimir Dinets account of a week in each country. Species include: in Congo-Brazzaville – Black-legged Mongoose, Red-fronted Duiker; in Gabon – Northern Talapoin, Black Colobus, Red River Hog, White-collared Mongoose, Mandrill, and Cameroon – Drill, African Manatee and a swag of rodents, shrews and bats everywhere.