FL Studio demo limitations:
The only limitation is that projects can be saved but can't be opened again.
To open your project again, purchase an FL Studio Edition including registrations for all instruments and effects used in the project. A lower featured FL Studio registration will open a demo project, but the not registered plugin(s) will be replaced with placeholders.
Some functions that need save/load to be active don't work in FL Studio demo. Examples are the "clone channel" function and the "Save preset as..." menu for plugins...
All other functions in the FL Studio demo are fully unlocked. Some plugins may give static (white noise) or silence at regular intervals as part of the demo limitations. FL Studio demo is the equivalent of the FL Studio Producer Edition + All plugins bundle package.
Remember, you can render to .wav, .mp3 .ogg or .mid files prior to saving a demo project.
Installation and registration instructions: