The game doesn't lock up your arrow keys. This means that whenever you shoot up or down, the window moves around. Please fix that.

I'm not sure what I'm supposed to do, but the controls do seem to work. It wasn't interesting enough to keep playing after the second time.

While in theory it looks like an awesome stand your ground game, functionality went through the roof for me on multiple levels.
Arrow keys also made my page scroll.
Eventually the "enemies" stop coming and I was left with flashing dots on the enemy entry points and nothing more. I don't know if this was game over or not. Now if players could shoot with mouse while defending with WASD and you addressed that game over bug this could become an evolving project for you in C3.

Awesome foundation you have, keep at it!