Could it be they're flipped? Set 2 is the original and set 1 has all the additional robot colors?
Ok, turns out this is correct. After playing set 1 a little longer IT is the revised version with the many colors of robots that shoot faster. I guess I didn't play long enough while checking set 1 to see the new colors. I was looking for green robots right away and neglected to read the part about "...a longer color sequence after the cyan robots".
After reading
this it seems the MAME team (or whoever dumped the roms?) made set 1 the later version since it was the most popular and set 2 is the original.
Do we start the competition over and have everyone use set 1 (which was the idea in the first place)? The robots shoot faster bullets, and more of them. It plays a bit different, and seems quite a bit more difficult