Here is the full list of all 12 Shank achievements worth 200 gamerscore. It takes around 10-12 hours to unlock all of the achievements on Xbox 360.
Complete the single player campaign on Hard mode.
Defeat Cesar.
Defeat El Raton
Defeat Cassandra.
Defeat the Priest.
Defeat the Butcher.
Perform 100 chainsaw kills.
Take out 1000 enemies.
Take out 100 enemies.
Take out 20 enemies.
Complete the single player campaign on Normal mode.
Complete the co-op campaign.