To mk fans like myself the exciting thing is that this arcade version would probably have the characters at their full resolution. The console and pc versions of this game had a decent amount of compression and omitted a lot of sounds and animations.
Of course (and assuming this vid isn't a fake) it's prototype status could mean that it's only in a psuedo-playable state.
Then again, I don't think anyone was even aware the midway thought of releasing a arcade version of mkt, so this needs preserved.