Galaga was by far my all-time favorite quarter stealer, but I got good enough that I could entertain myself for hours on one quarter.
600,000 points, 700,000 points, no problem. And that was BEFORE I learned the cheat!
There is a way to play which will cause the game to glitch and then all the alien bugs stop throwing bombs at you. Then your only hazard
is collisions. The vast majority of collisions happen in corner squeeze plays, so try to avoid the corners.
Once you're in the no atttacks mode, the game stays in that mode until you lose your ship(s) and have none to shoot with and have
to haul out a spare. As long as you have one in play, it won't reset.
You can play until you're very bored.

The cheat instructions are out there. Search them.
They do work.
CJ