Unreal

What’s Unreal? Jointly developed by Epic Megagames (now Epic Games) and Digital Extremes, the original Unreal was first introduced to the world as a "Doom killer." But after countless delays and the release of Quake, it was briefly written off as vaporware. Some doubted it would ever see the light of day. Fortunately, Unreal was finally released on April 30, 1998 after a then unheard of four to five years of development (the exact figure varies, depending on who you ask).

Unreal's original release was marred by a variety of technical problems. Poor network code made the online component barely functional and 3D support for certain video cards was quite shoddy. On the single-player side, some complained that the quality of levels sufferred as the game progressed, possibly due to the game's long development cycle.

Later patches fixed many of the original game's flaws and a thriving mod community did the rest. Unreal’s unique editor and powerful UnrealScript language spawned a vibrant, creative amateur game development community that is still active and growing today.