Full list of all 49 Watch_Dogs achievements worth 1,250 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 39 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 10 achievements worth 250 Gamerscore.
Take down Maurice
Complete 40 Fixer Contracts
Complete every Gang Hideout
Complete every Investigation
Complete every Privacy Invasion
Complete every Criminal Convoy
Use the Crime Detection System to take down 20 confirmed criminals
Complete Act 1
Complete Act 2
Complete Act 3
Complete Act 4
Complete Act 5
Perform 10 vehicle take downs
Using non-lethal takedown, stop 10 civilians from calling to report you
Tag 100 enemies
Participate in 5 different City Games
Kill 4 enemies within a single instance of Focus
Escape 15 police chases
Escape a level 5 police chase
Escape 15 Police Scans
Escape a level 5 police scan
Shoot out a tire on 15 different vehicles
Kill 3 enemies with a single IED
Complete the final mission in the Human Traffic Investigation
Complete the final mission in the Weapons Trade Investigation
Collect all 8 Burner Phones
Complete the final mission in the QR Code Investigation
Complete the final mission of the Missing Persons Investigation
Check in at every Hotspot
Unlock every song with the SongSneak app
Complete level 10 against all 3 Drinking Game opponents
Invade and successfully hack 10 enemy Fixers in Online Hacking
Invade and successfully observe 10 enemy Fixers in Online Tailing
Complete 10 Public Online Races
Complete every ctOS Breach
Complete an Online Tailing without being detected
Unlock every Skill in the Skills Tree
Get tailed 5 times
Unlock every ctOS Tower
T-Bone: Finish all main missions in Act 1
T-Bone: Finish all main missions in Act 2
T-Bone: Finish all main missions in Act 3
T-Bone: Complete 20 Chicago South Club contracts (including daily missions and driving missions)
T-Bone: Complete 20 Militia contracts (including daily missions and driving missions)
T-Bone: Complete 20 Fixer contracts (including daily missions and driving missions)
T-Bone: Complete 29 driving missions
T-Bone: Complete 10 coop missions
T-Bone: Complete all side investigations
T-Bone: Kill 4 enemies at once by blowing up the RC Car