Oh, you can get 2 of each boosters (Swedish fish, lollipop hammer, free switch, and color bomb, if I'm not wrong) by passing all 6 levels in a row, but you need extra effort to pass all levels and of course, luck.
Yeah, this event was not easy as I did. Extremely impossible if completed all 6 levels without boosters. But reward from this event is absolutely amazing. I want it but I give up to complete this event. So, I lost them all... Anyone else?