Here is the full list of all 39 Blacksad: Under the Skin achievements.
Complete the Hall of Fame album.
Complete the game without dying a single time.
Complete the Boxing sheet of the Hall of Fame album.
Complete the Baseball sheet of the Hall of Fame album.
Watch all 6 alternate scenes at the end of the game.
Help the Colberts live a second honeymoon and receive their gratitude.
Stand up to Sam as many times as you can.
Complete the Football sheet of the Hall of Fame album.
Complete the Hockey sheet of the Hall of Fame album.
Get hired twice for the same case.
Find all false endings in the game.
Do not take the case.
Stand up to Quince as many times as you can.
Play good cop convincingly.
Play bad cop convincingly.
Why's that poster in Dunn's flat?
Do not scare Brunhilda while telling her a story.
Contribute to as many deaths as possible.
Complete the game dying less than 9 times.
Now for real.
Complete all deductions in the game.
Solve the case.
Take your sixth beating.
Beat someone up for once.
Play baseball.
Complete Blacksad's silence conveniently.
Take your fifth beating.
Interact with as many books as you can.
Put your acting skills to the test.
Charm Helen Moore into giving you a present.
Take your fourth beating.
Buy a box of cigarettes from the nursing staff.
Take your third beating.
Take a ride with the city's most honest bookmarker.
Buy your favorite goat a second burger.
Take your second beating.
Take 400 nightstick blows. Maybe a few less.
Find your most valuable tool.
Take your first beating (spoiler: it won't be the last!).