On the upgrade select screen scroll through the Kongpanians. If you've earned any on the Kong website (normal and shiny) you can get a bigger X2 and X3 upgrade bonus.
That last ball was by far the hardest factory ball out of all series. Immensely satisfying to complete though.
Great job Mr Bonte - I hope you make more.
Excellent game - very clever. Shame a glitch causes sticky keys which causes me to repeatedly run to my death. Given up on getting the two harder badges.
 "Curl Up and Fly!"){kind=icon}
 "Factory Balls, the Christmas edition"){kind=icon}
 "Jelly Lam"){kind=icon}
 "Synapsis"){kind=icon}
 "Fold"){kind=icon}
 "SHIFT 2"){kind=icon}
 "The Fancy Pants Adventures"){kind=icon}
 "Dangerous adventure"){kind=icon}