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