Galaxian was a fun shooter game but then came the sequel, Galaga, which I enjoyed exponentially more... especially when my ship was captured and once I freed it I had double the firepower to blow those aliens out of the sky with. Then came the next sequel, Gaplus, that didn't have the same "fun" experience as Galaga.
Then Galaga '90 was released for the TurboGrafx and I was pretty excited at first. But I found the game to be overly complex for a shooter and you had to learn all the abilities of a bunch of new classes of enemy ships. The only saving grace in my opinion was that your ships could still be captured, not once but even twice... giving you the ability to triple your firepower if you saved the captured ships.
I'm half tempted here to say "don't mess with a classic". Overall it is fun but lacks the spark of the fire from which it came.
I would say that the game play for this cartridge rates 6-10, controls 8-10, and overall 6-10. This game is a good diversion, but I feel it could have been so much better.