In the late 80s, and into the early 90s, the Personal Computer (PC) began to really overtake game consoles in terms of power. Yet even more key to this emerging success was the simple fact that out of the 80s came only 2 main computing platforms; IBM compatibles and Apples.
As time passed, more and more powerful hardware came out that was still 100% compatible with the older operating systems, such as MS-DOS and Apple's MacOS. Even today I can still play games from that time period on my Windows 7 PC with very little extra effort, such as Solar Winds from Epic MegaGames and Tetris Classic from Spectrum Holobyte.
Backwards Compatibility is a key feature that is implemented in hardware or a machine's operating system that is critical for helping the transition from one game platform to another. It is a lesson that most of the major game consoles are having a hard time learning. For example, even with modern consoles, the Wii has a means to run older titles. Even titles from obsolete platforms Nintendo once competed against, such as Sonic the Hedgehog for the Sega Genesis. However, the PlayStation 3, while it's first version could play older PlayStation 1 and 2 games, no longer does so. Interestingly, you can often find these first generation PlayStation 3's selling for as much or more than a new one.
To go back to the hardware again for a moment, it might be that a game runs fine on a given PC and hardware configuration when it's released, but with a few upgrades or even an entirely new PC, the game runs flawlessly, and with better graphics and detail. Thus, an upgrade actually improves a game itself, instantly making that game justify the hardware upgrade.
And finally, the last major factor involved in the growth of the PC gaming market at this time was the advent of Shareware. Shareware is characterized by a demo being given away for free, which can then be unlocked for the full game by sending the author a small sum of money in the mail and then either receiving a floppy disk with the rest of the game on it, or a special code to unlock the rest of the game. Most Shareware still in the unregistered form was very enjoyable and entertaining in and of itself. You could say that they were complete, but short games. Some famous Shareware titles include Doom, Commander Keen, and Descent. All of which went on to have sequels, and some franchises started in Shareware are still being developed today.
