Rules for Castle Wall
I don't generally makes puzzles larger than the standard 10 by 10 grids. I like to put tricky steps in puzzles and in larger puzzle they can get lost for people. Castle Wall has more widespread constraints and in a larger grid you can do things that wouldn't fit in a smaller grid. This is a tricky puzzle, which uses two techniques a lot. I haven't done enough Castle Wall puzzles to see how often they appear in other puzzles.
If people didn't know yet, clicking the image gives you the image in the original size. The size discrepancy is a bit bigger in this puzzle.