Here is the full list of all 30 Judge Dredd: Countdown Sector 106 achievements.
Find all the blueprints
Find the ultimate ending in any mode
Successfully pull off a Lawmaster Kick
Accidently knock down a group of old folks
Take down a cannibal with a large appetite
Arrest a perp for breaking health regs
Kill three perps in one move
Kill two unusual creatures
Use ricochet rounds
Ride a powerboard
Roll two ones in a single roll
Roll two sixes in a single roll
Use your Bootknife
Abseil down a building and through a window
Enter Harridges from the front and back
Get to know all of Sector House 106
Achieve a Lawgiver Skill of 10 or above
Use armour piercing rounds
Use explosive rounds
Find all the Vitality bonuses
Find the ultimate ending in Hardcore mode
Find all the illustrations
Visit all active locations in Sector 106
Kill or arrest all perps connected to data from the briefing room
Take down a gambling den
Be responsible for the destruction of a pot-plant
Arrest 5000 perps in one go
Take down a Robot
Find all the perp records and data
Find all the mysterious VoD devices