I got one!
If this is considered a shoot em up, then it is my all time favourite (beating Swiv by alot)
The game I speak of, is Gyruss.
I think this game is in the arcade, but I've only ever played it on the C64, and I must say that no matter how much I play it, it rocks!
The graphics aren't great (the game was made in 1984
), but the sound is really cool. It also plays fantastic and lasts really long (I have yet to complete it, although I have gotten close)
I seriously think this is my all time favourite
Sorry. No screenshot. I'm feeling a bit lazy right now