Route-Out Puzzle from 2013 and Route-Out 2: A Thinking Puzzle from 2015. I loved them both.
The objective is to place various chess-like pieces (missile launchers) on the grid to fire their missiles into the castles and other missile launchers. A chain reaction must take place.
Of course there are brick walls which are blockers.
Some castles need multiple missiles to bring down.
These puzzles get hard pretty fast!
Brad has the right attitude: he's creating puzzle apps as a hobby, with no expectation of making any real money.
This game reminds me of Combination from 2012.