Theres some secret: at the gliders, go to the last page then click under the last glider. Destroy anything with the secret glider, go to achievements then click on the 8th secret medal. If you are in the ground, use a strong rocket to make a "snow mountain" and if that big enough, Zeus help you(works only 1 time). Enjoy.
 "Papa Louie 2: When Burgers Attack!"){kind=icon}
 "Bloons TD 5"){kind=icon}
 "Ninja Warz"){kind=icon}
 "Super Adventure Pals"){kind=icon}
 "Bad Eggs Online"){kind=icon}
 "Kingdom Rush"){kind=icon}
 "Platform Racing 2"){kind=icon}
 "Learn to Fly 2"){kind=icon}