Here is the full list of all 8 Humanity Must Perish achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Give mankind one more chance
Condemn mankind to extinction
Spark the interest of a moral young man
Spare the life of a delinquent
Become friends with an otaku
Impress an elementary school child
Encounter the dog-walker and his pet
Finally escape from the professor's lab