Here's the short review: If playing a really good arcade version of Space Invaders with all the game variations from the Atari 2600 version sounds like fun, this game is for you.
Space Invaders was the first "killer app" for the Atari 2600. Very popular in arcades, the home version is a pretty good recreation even today. Sure the invader designs are a little different and there aren't quite as many invaders and shields on the screen; it's still way better than say the 2600 versions of Defender or Pac-Man. Plus, it comes with a crazy amount of game variations: moving shields, zigzaging bombs, invisible invaders, two player coop, and more.
Today you can get "arcade perfect" Space Invaders in either one of the many Taito compilations for modern consoles, or the excellent Space Invaders Collection for Colecovision, so if a version for the Atari 7800 was going to be special, it needed to be more than just another port.
Combining arcade Space Invaders with the game variations from Atari 2600 port was a great idea, and the results are excellent. Being able to choose the color palette is icing on the cake. Space Invaders is a simple game by even classic standards, but if you are an avid Atari fan, I can't imagine you not liking this game.
The Homebrewing screen on the 7800 is really getting interesting and is the main reason I got back into the 7800. Many homebrews are now as good, or better, than the official releases. As of this writing, this game was a limited release. Hopefully there will be another printing, as it belongs in every 7800 fan's library.