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