Here is the full list of all 21 Kick-Ass 2 achievements.
Finish off Chris D'Amico once and for all
Defeat Chris D'Amico's thugs
Defeat Mother Russia
Survive the battle for Manhattan
Cross out the 24 graffities
Find all the Wi-Fi hotspots
Get rid of the Tumor
Cross Central Park
Chase the Tumor through the sewers
Escape with your life from the Cemetery
Survive the clash with Mother Russia
Defeat Genghis Carnage
Reach Genghis Carnage's whorehouse
Leave the subway
Reach the entrance to Headquarters
Eliminate all the enemies in the Justice Forever Headquarters
Defeat Black Death
Cross Chinatown
Fight your way through the Goths to the subway entrance
Reach the Goths' Lair in the subway
Rescue Dr. Gravity