Future Demoness is a very hard/insane demon by MaJackO. It's considered to be his hardest level.
The level's original song was: "The Quick and The Dead" by Rudebrat, but it was then removed from Newgrounds and MaJackO replaced it with Supernova. The level isn't synced well with the music because of that.
The level starts with some moderate jumps, fake lines and many jump rings. And then it becomes even harder when it turns into dual cube. And then it turns into a difficult UFO with tight spaces and spikes everywhere. And then it becomes extremely hard with dual wave due to fake spaces and extremely crucial timing. It becomes less harder (Still very hard) with it being single. And then the player will transform into cube again, right before a difficult ship. It hops between segments like that until the ball part with many, many traps and gravity changes that needs crucial timing. And then it turns into a very difficult wave with tight spaces, high speed and traps. And then it turns into a very hard ship with slow speed. Then it turns into a even harder wave with traps hard to notice, tight spaces, high speed and constant gravity changes. And then it turns into a very difficult fast mini ship that needs memorization. Then the level will end with a wave with the word "Thx". However, it will turn into an easy cube again before the level ends. However, it is possible to skip the cube portal easily by staying at the ceiling, causing the secret way. And then the level ends.