They simply didn't have the resolution or the graphical processing power to do it. However, unlike Asteroids, it was difficult to take the crisp clean graphics that defined Tempest, and port them successfully to early home consoles. Tempest was quite a success at the arcades. The player is given one alternative "Zapper" weapon to use each stage in case of emergencies.
Enemies are only vulnerable as they are rising out of the well, and enemies that make it to the outer edge become especially dangerous for the player. You control a weapon, with the dial, that can circle around the outside edge of the well (assuming that it's circular, some boards are not) firing shots down each of the columns. The object of Tempest is to destroy every enemy that is attempting to climb out of an electric well. This made Tempest stand out equally among monochrome vector games and colored raster games.
However, since Atari used vector displays in quite a number of games, they developed a technique to display vector graphics using different colors. Previously, vector monitors can only produce black and white images, or at best, shades of gray. Tempest was an arcade game, developed by Atari in 1980, and was the first game to make use of Atari's Color-Quadrascan technology, which was a colored vector display system.