I always have a love for games where you barricade and defend things! Had a lot of fun.
A couple of my thoughts on how things could be improved if you are interested:
-Clicking on projectiles to harm them isn't really viable at this screen size. Maybe consider making the screen wider if you want that to be an option?
-Being able to rotate pieces could help a lot with build variety.
-Some defense types other than walls could be cool!