There was no prototype. There where several complete products you could even try in a private room. Now that was a few weeks ago and still no video. Look at the montage how many videos there are.
Still they where prototypes, it was posted several times by Mike Martin.
However Casio will release the instrument Next Month, end of March.
Currently some top music people, like Ralf Maten (buddy of Kurt Ader) have a MZ-X prototype at their homes and are creating content for it.
If you would have taken some time and read the facebookgroup you would have known these facts...