Instructions
Stand next to the controller in your Pod and press the "square" button. Select "Story" from the menu than appears.
Progress through the first seven worlds by completing each of the three stories within. You'll need to finish The Gardens, The Savannah, The Wedding, The Canyons, The Metropolis, The Islands and The Temples in order to unlock access to The Wilderness.
Complete the first level of The Wilderness, The Frozen Tundra, in order to access the remaining three levels. You need to complete the second story level, The Bunker, to unlock the Neon skin. If you "Ace" the level, that is, complete it successfully without dying, you will also receive the Neon Helmet and dress.
Press the "square" button at any point after these items have been awarded to access the "Pop-It" menu. Select "Customize Character" from the right side of the menu. You can now select the Neon skin from "Materials" and the other items from the "Clothing" sections.