Level editor
 

where can i find the level editor???

Re: Level editor
 

ArrowVortex, DDReam and StepMania editor are all popular different level editors for 4-key rhythm gaming. Suggest starting your search there.

StepMania & Etterna can both play files created by those level editors.

FlashFlashRevolution doesn't specifically have an editor. Songs are created through the level editors above, and then submitted to the website for review. If they pass quality assurance (song submission judgment), then they get converted to flash and put into the game.