The letters in the shaded squares will spell out the answer.
This pattern looks pretty familiar. It's a 9x9 grid subdivided into 9 3x3 grids. Some of the grid spaces are filled in, but most are blank. We're provided with the following 9 letters.
B A S P O I L N G
Yep, this looks like sudoku. Dealing with 9 assorted letters is a little inconvenient, so let's map them to numbers and tackle it the normal way.
A = 1, B = 2, G = 3, I = 4, L = 5, N = 6, O = 7, P = 8, S = 9
That's a lot easier for me to deal with. Now just solve like any other sudoku puzzle.
Et voilà! Now let's turn those numbers back into letters.