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