Solve the puzzle and get a "prize"

To access your "prize"

All the boxes filled in? Here we go.
1 –> 3 down from 9’s start
2 –> 5 over from 6
3 –> One away from 10
4 –> The last of 3
5 –> Start of 18
6 –> Middle of 11
7 –> 3 away from the finish of 4
8 –> Second to last of 16
9 –> Again, the last of 3
10 –> 6th letter of 14 across
11 –> Where 4 and 6 meet
12 –> The last of 12
13 –> The first of 7
_ _ _ _ _ _ _ _ _ _ _ _ _ (no spaces)
Got the code? Click the button.