Thanks a lot for the review!
Yeah it might have been a good idea to leave the total score on screen or to summarize how the score is calculated at the end of a level.
To summarize :
If you break windows you lose points, if you patch the walls (until you hear the sound and see the points added) you earn points. The more buildings you clear the more points you earn. If you go to the top of a building without patching any holes you lose a lot of points.