In Shape Defence you're a cannon in the middle of the screen fending off the different shapes that come your way. Some come at you quickly while others are very slow. If they hit you you will lose health. You accumulate gold with every kill you get and every level you reach. Once you get gold you can start purchasing weapons. Save your gold to get the most expensive weapons first or buy them as you go. Every weapon has different strengths and weaknesses. You can also buy health in between levels but not during. This is a fast-paced game that will keep you playing for hours.