AURORA: Set near the North Pole, the Aurora World adds gusty winds to the mix that can blow your fireworks off course. If the sparks and bullets become too thick, create a vortex to suck them in by drawing a spiral with your stylus. Use this temporary upgrade as you make your way through the all of the world’s levels to the Rock n’ Roll Walrus boss. Keep your eyes on the snowfall to determine the wind direction. Using the Vortex will also absorb your debris, allowing you to fire at will. Certain ice blocks can be shot at, or can be shattered with a tap of the stylus. During the boss battle, watch out for danger from the bottom of the screen. World Upgrade: Vortex: Quickly draw a spiral on the touch screen to create the Vortex. Use it to absorb enemy fire when the going gets tough. Remember to let it recharge between shots. Also, upgrades, permanent or otherwise, cannot be used during boss battles!