There are two variables for the score, the "total" score is the actual score (which is not seen), but the score value on the screen is the other variable. if the onscreen score is less than the total score, add some more to it to get it closer to the total until it's equal :) It checks every frame, so 60 times a second. It adds 10 points a go, unless that will go over, then it adds 1 point each time.
The cloud is a "powerup" that if it's hit with 5 pitchforks in a close amount of time - then it starts 'raining' pitchforks ! Very bad for the crows, but you are fine, assuming you are wearing your hat when it rains ;)