Read TheBooBooKitty's writeup above to read the main info about this game, what is below is a description of what it was like to play this game. (And I should know, I've played this game for hundreds of hours.)
This game was fun, despite being extremely repetitive: You were a small UFO and there were three laser bases on the ground. Always three. You could either move around with the joystick, or you would press your fire button, and then press the direction you wanted your laser to fire. If you hit a base, it was destroyed. If the base fired at you, you lost a life.
They would be firing at you with increasing accuracy, but they had a delay before they were allowed to fire at you. You destroy all three bases and then you go onto the next, faster, level. Eventually, you got free lives after a few levels. I remember the free lives being in short supply when I first got the game, and then feeling like they were overgenerous after a while.
In the classic style of the game you "cannot win," it would just get harder and harder as you played. But for some reason, that delay before they fired always stayed at a "reasonable" amount. So, if you got into the "groove" and could destroy all three before they were allowed to fire at you. (And if you missed, you were in the right spot where you would be unable to be shot at.)
I got into that groove. For hours at a time, for days upon days. For some odd reason, I didn't think that after 6 hours of playing that the game would actually keep going on. But, this is one of those games where I definitely qualified for that little patch that they would give out. Well, heck, I rolled the score over and could get maximum free lives. (But never sent in for the patch, because I never thought about it.)
But, to this day, I think I can make the appropriate hand movements to win this game. For hours.