Hmm.... when I was back in high-school in '80 I watched one of the
guys I went to school with score 70k on Space Invaders Part 3.
However, I have yet to see the particular version of Space Invaders
Part 3 that we had in the local arcade.
After completing the 1st stage it gave the opportunity for entering
The stage number was included in the graphics of the protective bases.
Every 3rd stage the invaders didn't move and you had a time limit to
shoot them all - with 1000 bonus points for getting them all within
the time limit.
The "rainbow" bonus was worth 1000 points and consisted of the screen
being "split in 2" vertically by a zig-zag line and then filled in an
anti-clockwise spiral from the middle of the screen by what looked
like stylised paw prints.
The motherships alternated between 300 point standard motherships,
assuming you were counting your shots, and 500 point flashing
It was far-and-away the best version from a player perspective
because it never got impossibly difficult and had the best bonuses
for the "rainbow" bonus. It was also the only version I saw that had
the 1000 point timed stages every 3rd stage.