List of unused content of Super Smash Flash 2

The following list consists of unused content that was originally planned to be included in Super Smash Flash 2 before being scrapped. Additionally, any unused or removed music tracks will instead be listed here.

Characters
Several characters were initially planned to appear on the playable roster:
 * Rock Lee and Sasuke Uchiha from the  franchise. While Rock Lee's Final Smash was never revealed, Sasuke's Final Smash was planned to be his Cursed Seal form, a Transformation Final Smash meant to improve drastically his moveset, with new attacks and options. Rock Lee was instead included as a background character on Hidden Leaf Village.
 * Vegeta from the  franchise. His Final Smash was planned to be his Super Saiyan form (like Goku's); a Transformation Final Smash meant to enhance his current attacks while also adding new moves. He was instead included as a background character on Planet Namek.
 * Renji Abarai from the  franchise. His Final Smash was planned to be Bankai: Hihiō Zabimaru, where he would turn his Zanpakutō Zabimaru into its Bankai form, then send it into the ground in its Shikai state and having numerous blades sprout from the ground. He was was instead included as an Assist Trophy, but he was later removed in Beta.
 * Fan characters Blade and Blue, along with newcomers Azrael, Robo Ninja, and Spikeman. All five characters were planned to be in the game prior to 0.7, though plans changed when the game's creators fell out of touch with the characters' creators.
 * Mega Man X, using his Biometal form from Mega Man ZX. He was replaced by the original Mega Man.
 * Riku from the  series. He was instead included as an Assist Trophy.

Special moves

 * Chu² Bomb was planned to be ' side special move. Tails would put a small bomb on the ground, which would dash forwards and explode on contact with a foe, or after five seconds pass. It originates from ', where it appeared as Tails' Ground Trap attack. The bomb is similar to a Chu Chu from ', another game made by SEGA. Its concept is very similar to that of Remote Robot, Tails' up special move as of Beta 1.0.3.
 * Tengu Blade was initially intended to be 's side special move. He would throw a large energy blade through the air, which would spin around for a while before returning to Mega Man. The move debuted in .
 * Black Hole Bomb was originally supposed to be his down special move, but it was scrapped and later incorporated into Mega Man's Final Smash, Mega Legends.
 * Angel Ring, Pit's side special move in Brawl, was planned to be 's side special move in SSF2.
 * F.L.U.D.D. Tornado was planned to be and Fire Mario's down special moves in demo v0.4a.
 * Energy Release was planned to be 's down special move in Super Smash Flash 2. Similarly to Kaiō-ken, Goku would release energy around him. It was heavily hinted that the move would get stronger depending on Goku's damage.

Stages

 * Skyworld was originally revealed in a screenshot for v0.8a, though the stage has yet to be added, multiple years later. It did, however, exist hidden in the game's data until v0.9b.

Items

 * Light Yagami was planned to have a completely different effect before his debut in demo v0.7, where Ryuk the Shinigami would drag opponents to a blast line.
 * Clyde's Shoes were supposed to appear in SSF2. Equipping them would make the player move noticeably faster for a set period of time.
 * Battle Cards were confirmed to appear in-game, but were removed, as the developers found them too similar to Assist Trophies.
 * The Boost Pad, from the  series, was planned to be an item that could be placed on the ground, similarly to the Motion-Sensor Bomb, and gave players a momentum boost in a set direction upon contact with them.

Modes

 * Adventure Mode: The Flash Of Shadows was a planned story mode. Whether or not a new story mode is being developed, though, has yet to be announced.
 * Classic was originally planned to have a new feature called the "Peril Roulette", which would have given advantages to the opponent or handicaps to the player, depending on the difficulty setting, but the feature was ultimately scrapped.