An unlockable stage is a stage that is not available at the start of the game (unlike a starter stage), but must be unlocked. Like an unlockable character, it is required to accomplish a particular in-game feat and once completed, a message will be shown, telling the player that the stage has been unlocked.
In Super Smash Flash
|Battlefield||Clear All-Star mode with any character.|
|Final Destination||Unlock all characters.|
In Super Smash Flash 2
For the final version, any information is unknown.
Three stages were unlockable in early demos.
|Chaos Shrine||v0.7||Unlock Black Mage.|
|Clock Town||v0.8||Accumulate a total of less than 5 minutes with all starter characters in Target Smash!!.|
|Sand Ocean||v0.8||Play 10 Brawl matches with Captain Falcon.|