Stormwinds

This is a cross between a desktop defender and point and shooter. Build your base and defend it from wave after wave of enemy sky vehicles and ground machines. I think there is a definite knack to this game because I'm incredibly bad at it, either that or you need to start on the easiest level as there's a steep learning curve, one of the two.

Mouse to aim and shoot.

I recommend getting the machine gun early as it really mashes through your enemies.