Here is the full list of all 20 Boo! Greedy Kid achievements.
Finish a level with just one hearth remaining
Get tased
Slam a door in the face of someone
Slam a door by rolling through it
KO a nurse
Finish your first level
Shout on your first victim
Taunt someone with your butt
Shout on 200 persons
Finish one third of the main campaign
Finish two third of the main campaign
Finish all levels
Get one third of all the stars
Get two third of all the stars
Get all stars
Hide behind a furtinure 100 times
Dodge roll 100 times
Get caught by a robot-cop
Earn $5000
Shout on a SWAT