Here is the full list of all 18 911 Operator achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Awarded for working in 15 different cities.
Complete a duty without overtime on Hard/Expert difficulty
Complete the Single City Run
Awarded for reaching high experience level (any team member)
Awarded for long service (30 duties)
Awarded for finishing 3 duties in a row without any death or major mistakes (less than -3 reputation)
Complete the game on Expert difficulty
Awarded for finishing the campaign
Awarded for special tactical skills (gather 3 police teams before shooting starts)
Awarded for resolving a case despite death of your team member
Awarded for keeping the roads safe (Resolve 50 driving reports)
Awarded for a sense of humor ;)
Awarded for resolving 50 fire or technical cases.
Awarded for gaining 100 reputation points on one duty
Awarded for saving 50 people by driving them to a hospital.
Awarded for saving a life by giving proper first aid instructions
Awarded to those wounded or killed while serving
Awarded after finishing the training