Ultra Fatality

I think the question should be what's the difference between an Alpha and a Beta.. ; )

A hint that you'll be releasing something very soon?
Or not??

A demo is essentially a 'taste' of the full game, whether it be playing through a specific section of the game or a completely original scenario that doesn't spoil the game but lets you know what it's about.

A beta is an unfinished game, but is considerably more complete than an alpha. It usually gives an accurate representation of the full game, but features are missing/unfinished and bugs are present.