Here is the full list of all 20 Shank 2 achievements.
Complete Campaign Mode on Hard difficulty
Complete Campaign Mode on Normal difficulty
Find the kitchen sink and kill someone with it
Rescue 50 Civilians From The Militia
Execute 150 kills with the baseball bat
Kill 50 enemies with the heavy object smash
Kill 100 enemies using the shovel
Beat a Campaign level with no ranged attacks
Perform 100 Machete Counter Kills
Perform 60 Pistol Counter Kills
Do 10 combos of 20 hits or more
Reach the zombie wave in each Survival map
Defeat all the waves in any Survival Mode map
Get 30 firetrap kills in one Survival match
Do 30 counters in one Survival match
Kill a Survival Boss with no traps or grenades
Buy everything in Survival Mode
Go 15 waves without either player dying in Survival Mode
Buy nothing for 10 straight waves of Survival
Kill 12 enemies