In the Kid Icarus series, Skyworld is where gods and angels live in harmony. Late in the story of Kid Icarus: Uprising, however, it falls apart, and the ruins of Palutena's Temple have become a stage to battle on. The bridge can be destroyed, splitting the stage in two, but you can still cross the gap using clouds or moving platforms.
Palutena's Temple is based on how Palutena's Temple in Kid Icarus Uprising. Each part is based on each part of the levels taking place in the Temple. The Palutena statue in the background is much like the one Palutena uses to protect the Temple from invaders with her divine powers.
The Guidance with Dark Pit hints at the fact that Super Smash Bros. for Wii U happens soon after Kid Icarus: Uprising's ending and hints at some sort of sequel with Dark Pit fighting with Viridi and the Forces of Nature.