Tempest is one of several famous classic vector-based arcade games from the early 1980s. Vector graphics are really neat because, rather than the modern approach of placing pixels on what is essentially a square grid (not much different than graph paper – it’s called rasterization), they were lines that were drawn between two points – perfectly. Modern raster-style graphics have the advantage that it’s easier to display much more detail, with the downside that lines often have aliasing artifacts. Vector graphics have no aliasing, but each line drawn is computationally expensive, so everything is generally simple line graphics.
Source: N4G PC Tempest 4000 review – ChristCenteredGamer