If you haven't seen an Asteroids cabinet in action, I suggest you find one at an arcade museum near you. Actual Asteroids is quite different from any port or emulation of it. The slow-decay phosphor leaves visible trails for your ship and shots, and the machine has control over electron-beam intensity in a way that raster units do not, which means that your shots and enemy saucers glitter in the dark, creating a "spacey" atmosphere that's hard to replicate on a raster display.