Sky Sanctuary Zone

Sky Sanctuary Zone is a starter stage in Super Smash Flash 2 coming from the  series, based on the location of the same name originating from the game Sonic & Knuckles. It was confirmed for inclusion in the final SSF2 v0.8 Dev Blog in October, 2011.

Layout
This stage mainly consists of one large platform, which is slightly raised on both sides, and two wide soft platforms above it. With stage hazards turned on, there is a series of small block-shaped platforms spanning diagonally to the blast line on each side of the large platform. Upon standing on one of these blocks, it will shake momentarily before falling down, after which it will shortly reappear.

Music

 * The main music track is the self-titled Sky Sanctuary Zone, a soft orchestral remix of the theme that plays on the level of the same name in Sonic & Knuckles.
 * The alternate music track is Sky Canyon Zone, a 16-bit remix of the theme that plays on the level of the same name in Sonic Advance 2.

Tournament legality
Sky Sanctuary Zone is a counterpick in tournament play. The long floating platforms, combined with the sunken-in central area of the stage, make it very difficult for a player to claim control of the stage if their opponent has already assumed control, as the edges of the sunken region prevent ground approaches while the long platforms hinder aerial approaches. The stage also has a somewhat low ceiling and shorter-than-average side boundaries. Furthermore, the slopes on the main platform can lead to strange interactions with various characters.

Over the course of the game's development, this stage had a controversial history in competitive play, in part due to the elevated ground initially consisting of walls rather than slopes. These walls became larger in Beta, leading the stage to be banned until later being changed.

Origin
Sky Sanctuary Zone first appeared as the sixth level in Sonic & Knuckles, as well as the twelfth level in Sonic the Hedgehog 3 & Knuckles. It is a holy collection of ancient ruins in the sky above Angel Island, and it is forbidden for anyone to enter besides Knuckles. After Dr. Eggman escapes from Hidden Palace Zone with the Master Emerald, Knuckles and Sonic (and often Tails) chase after him. Knuckles leads Sonic to the Sky Sanctuary Zone via a warp, and Sonic follows Eggman on board the Death Egg, fighting Mecha Sonic numerous times along the way, though Knuckles does not follow Sonic to the Death Egg. The layout of the stage is reminiscent to the layout used during the second boss encounter with Mecha Sonic.

Trivia

 * If the player looks closely, an Eggrobo flies past the stage in the background.
 * As confirmed by developer James Hadden, the bouncy clouds from the first design were later recycled to make the trampolines and flippers in stage 3 of Target Smash.