This is a very early and very different looking version of
Xevious. While an actual prototype for this version has not
yet been found (if it was ever burned onto EPROMs), it was
featured in the Atari In-House Promo 2nd Quarter 1983 video which
was made to show other Atari employees what everyone was working
out at the time. This early version of Xevious appears to be
nothing more than a movement demo showing off some different
looking enemies that move together in a block like pattern while
the the background scrolls underneath. There appears to be
no collision detection implemented as the player moves through the
enemies several times during the video.
Other interesting things to note is that your ship has a proper
sprite and targeting box rather than being made up of two angled
pieces and a simple dash for the targeting box. In addition
to being bright blue, the background is somewhat glitchy in this
version especially when the wider sections appear. There
also appears to be no score or lives counter.