There are two types of power-ups: “skills” and “map.” Skills power-ups can make you run faster, make you immune to fear, or give you weapons to defeat LightEaters. “Map” power-ups allow you to view the key, exit, or the full map while you play a level.
Power-ups can be purchased with Cola Currency in the power-up shop, which you can get to by clicking the orange rocket icon on the bottom of the main screen.
When you play a level, power-ups will appear at the bottom of the screen, and you can click the icons to use them during gameplay. Keep in mind that power-ups will not appear and are not usable for the first three levels.
For more information regarding Cola Currency and how to purchase Cola Currency, go here.