Geometry Madness

So you were at home (obviously at Geometry Island, who doesn't know that?) and suddenly... A GIANT SPACESHIP that looks like a triangle FALLS down your world. Shapes are invading and destroying your friend's island, EVERY 5 ISLAND. So you decide to save your world, risking your life at all costs, passing in each island without fear, figthing upon fear. And how's that going to end?? You don't know.