In December 1992, Computer Gaming World reported that DOS accounted for 82% of computer-game sales in 1991, compared to Macintosh's 8% and Amiga's 5%. In response to a reader's challenge to find a DOS game that played better than the Amiga version the magazine cited Wing Commander and Civilization , and added that "The heavy MS-DOS emphasis in CGW merely reflects the realities of the market".  A self-reported Computer Gaming World survey in April 1993 similarly found that 91% of readers primarily used IBM PCs and compatibles for gaming, compared to 6% for Amiga, 3% for Macintosh, and 1% for Atari ST,  while a Software Publishing Association study found that 74% of personal computers were IBMs or compatible, 10% Macintosh, 7% Apple II, and 8% other. 51% of IBM or compatible had 386 or faster CPUs.  By 1992 DOS games such as Links 386 Pro supported Super VGA graphics.  While leading Sega and Nintendo console systems kept their CPU speed at 3–7 MHz , the 486 PC processor ran much faster, allowing it to perform many more calculations per second. The 1993 release of Doom on the PC was a breakthrough in 3D graphics, and was soon ported to various game consoles in a general shift toward greater realism. 
A video game, like most other forms of media, may be categorized into genres . Video game genres are used to categorize video games based on their gameplay interaction rather than visual or narrative differences.   A video game genre is defined by a set of gameplay challenges and are classified independent of their setting or game-world content, unlike other works of fiction such as films or books. For example, a shooter game is still a shooter game, regardless of whether it takes place in a fantasy world or in outer space.