Good Points

You score points for packing cards of the same suit into descending sequences. The longer the sequences the higher your score:
3 packed cards+100 Points
4 packed cards+250 Points
5 packed cards+450 Points
6 packed cards+700 Points
7 packed cards+1000 Points
8 packed cards+1350 Points
9 packed cards+1750 Points
10 packed cards+2200 Points
11 packed cards+2800 Points
12 packed cards+3500 Points
13 packed cards to the foundations+5000 Points
Turning over a face down tableau card+250 Points
(max = 3000)

Bad Points

Every second of elapsed time-1 Point 
Every time Undo is used-50 Points

Completion Bonus

When the game is completed, you will receive a bonus calculated in the following way:

Bonus = (End of Game Score / 25) + ((300 - Time Taken) * 10)

If you completed the game in our usual, impossible, hypothetical, zero seconds, then the maximum possible score would be:

23,000 + (23,000 / 25) + (300 * 10) = 26,920

Completing a game of Scorpion in 3 minutes without using any Undo's would give you a very credible score of 24,932 points.