[Death by Mirrors]

Pessi, I have a possible solution for the entire puzzle, but I'm sure there are several. Anyhow, in order to solve it you have to look at the numbers in each row and column.

For example in the bottom row (row 10) it says "7". Which means there is one long block made up of seven individual squares. Now the black squares in that row have already been correctly guessed. If you count them, you'll notice they are 7. This means A10 can't be a prize, because otherwise the given number would have to be 8 instead. It also means J10 can't be correct, because then the hint would've been "7 1".

Now take a look at row H. There's supposed to be a block of 2, and we have that - it's H1 and H2. Now that means H3 can't hold a prize, because otherwise the hint wouldn't be "2 3 1 1" (it would've been something like "5 1 1" if there was a block made of 5 squares). H4 and H5 however are only two squares, yet the number given indicates it should be three. So that makes H6 a safe bet, and then once again the block is finished, meaning H7 has to be empty.

Now remaining in column H are two individual blocks of one square each. Remember, if they were adjacent to each other, the hint would say 2 instead of 1. One of those two squares has already been found out (that's right, I'm looking at you, H10), but now you should be able to identify the other one. Good luck!