The version is very close to being complete but lacks the
Trak-Ball support from the earlier version. This version
also has a serious bug where a Xari can get trapped in the center
well and cannot be destroyed. This bug is somewhat rare, but
will effectively end the game should it occur. The computer
AI isn't as polished as it is in the final version and usually
gets killed around level 18 or 19. Interestingly this
version has a secret message and ending that is revealed after
beating the game. It is unknown why Atari took this out.
Prototype
Differences
There is no Trak-Ball support
The computer AI isn't quite as good as it is
in the final version
This version has a special message at the end of
the game after beating all 32 waves, congratulating them
and telling the player to send a picture of the end screen
to John at Atari. This message was taken out of the
final version for some reason.
The computer will play itself if
you let it
Notice the unique font used for the
on-screen text
The last intermission forms the
programmers initials (JRS and CG)