Here is the full list of all 8 Dude Cops achievements. It takes around 0-1 hour to unlock all of the achievements.
Help the Old Lady across the "street"
Teach Lil' Timmy a valuable lesson
Remove the pesky mouse
Does Dracula wear boxers or briefs?
Have a pleasant chat with a zombie
Rescue the lost ball
Examine the barrel
Save the cat from the tree