RAINBOW ISLANDS TOWERING ADVENTURE

The video below was prepared by TodaysForgetten.

There are two ways of getting this, but either way you'll have to defeat all ten bosses that appear between 0m-9,999m. You must destroy all ten, rather than jumping up and avoiding the boss battles. With all bosses beaten, you will unlock the true final battle with the Crimson King. Instead of attacking him, shoot your rainbows quickly and walk up them. This will lead you off the top of the screen. The boss will continue doing his thing, while you keep climbing. Make sure to move left and right every once and awhile, as you will hit the edges. Repeat this until you reach 10,500m. As your falling back down, you should also get "Questionable Talent." Notice the character is off screen but the meters are still going up.

You can also reach 10,500m by actually beating the Crimson King, and chasing after Holly afterwards. Skip ahead to 3:00 in the video to watch this alternative method of reaching 10,500m.