unity game development -- 2

Display a jaw mockup with teeth with stains
the mouse will be a tooth brush displayed on screen
-user should use the mouse to remove the stains
-user have to use the brush to remove these stains
-when stains removed, the teeth become white and a score is added
-a message displayed for couple of seconds when each teeth become white
-there is a time limit (1-2 minutes, to be decided later)
-a score is collected when each stain is removed
-when time is up, display score in full screen