Here is the full list of all 8 Playing History 2 - Slave Trade achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Talk to Wallace about the trip to Africa
Play "Find 10 errors"
Negotiate slaves with the chief
Find out the travel time for your journey
Play "Slave packing"
Find out if Akim has scurvy
Decide what to do with the lack of food
Play the "memory game"