I was soooo looking forward to play this game and glad it turned out to be such a satisfying loop!
The overall vector graphics work nicely. The stun mechanics were cool too! Thankfully, you allowed continuous casting rather than making player click the mouse button several times!
The music is pretty awesome.
When I first opened the game, the initial text was clear that I needed to convert the pirates into defenders. What Initially, I did not know how many times I needed to cast the magic to convert them. The progress bar at the top of each pirate would be even better.