I have just played a round and found something ugly...
It seems that some bosses can be milked a lot for better scores. but when I reached the 3rd boss I could simply stay at the same position and just hold the fire button to increase my score.
When I stay there I won't hit the boss, nor will he hit me. But my lasers will destroy his homing missile each giving 100 points. I just laid my joypad carefully on a book (upside down), so that the fire button will be pressed the whole time. Then I ate something watched a bit TV, about 30 minutes later I returned to my PC and was still increasing my score.
That's why I'd like to vote for another game, this week.
So how about: R-Type 3 (SNES) or Gun-Nac (NES)? Those two got the second most votes. From these two, my voice would be for R-Type 3.