The first puzzles
The third blanket
This suggest the following rule:
The last blanket
The last puzzle
The puzzle is completed!
So now we know the final solution!
Some more notes on the final answer
The difficulty level of sudoku is not determined by the amount of restrictions there are on the puzzle, but rather the level of skill and techniques required to solve the puzzle. The easiest of sudoku puzzles will require basic understanding of sudoku logic, whereas the hardest will require advanced techniques and understanding.
There is ...
Look at the 9th column (2,7,1):
Then in that row (4,9),
Then in that column (8,3),
That allows you to fill in quite a few cells in that column, which will then enable you to make more deductions in the relevant rows.
In the rightmost column
If it were are the bottom, row 17 (always included in the 6) would force the 7 in the next column to the bottom too, but it wouldn't fit because of the 1 on row 18 (also always included in the 6) forces r18c19 to be empty.
Graylocke has worked through an older version of the puzzle, which did not have a unique solution. If (s)he would had seen the updated puzzle, I’m sure that (s)he would have been able to solve it quickly using the same type of deductions which (s)he had been using.
However, since it’s been more than a year without any updates, I am posting my solution.