Iron Throne

Title: Iron Throne

Rating: 4/5

The hardest puzzle yet posted (in my opinion--as ever, feel free to post thoughts about the difficulty rating in the comments), and one that belies a fascination with a certain fantasy world.  If you get too frustrated, calm down: you don't want to lose your head.

The official rules:

• The digits 1 through 9 appear in each row and each column exactly once.
• Digits in each shaded region must add to the indicated sum.   
• Squares with multiple colors contain a number that’s used in the sum for adjacent regions of each of those colors.  
• Remember: numbers can repeat within a shaded region if that doesn't violate the first rule.