In this fast-paced industry where the state of the art is out of date 6 months before it even hits product shelves, the Unreal engine has shown remarkable longevity. First debuting with Unreal in 1998, not long after Quake II's release, the engine itself showed superior graphical capabilities than id's offering. Both engines have since been used in many games, but id has moved on with the Quake 3 engine while Epic just kept working away at Unreal, adding new features and improving the old. The Unreal engine is still going strong, soon to appear in games like Deus Ex and Rune, but Epic isn't quite ready to make a new engine yet. The improvements they are making will likely keep Unreal as a competitive product for a long time to come.
D3D and OpenGL support were added in multiple patches after the release of Unreal. Graphical and performance were continued with the release of Unreal Tournament, but there have been no particularly revolutionary enhancements done with Unreal. The D3D and OpenGL ports didn't actually introduce any new features aside from compatibility with non-3dfx cards. The enhancements made for UT were numerous but small, and any single change wouldn't be that noticeable, though the overall effect was rather dramatic.
However, this new technology that Epic is demonstrating at various conventions and shows is actually very revolutionary. Well, before we discuss why it's so dramatic, maybe we should explain what it is first.
What Epic plans to introduce to Unreal is rather simple, in concept. They want to do outdoor terrain, and they want to do it very well. In our talk with Brandon Reinhart at E3, he freely admitted that they want to look better than Bungie's Halo. After all, if Halo is released this year or even in 2001, Epic and Unreal licensees will need time to actually make games with the new technology. Unreal had better look good by then, since Halo and possibly other outdoor-based games will start appearing, likely with a big lead in release dates for the games.
The other problem that Epic found itself faced with was trying to create objects to fill the terrain. If you've ever played Tribes, you've seen how empty the world can be. Epic is planning on putting trees, shrubs and the like to fill out their world, but don't worry, it won't be like trying to run 100 simultaneous Treemark demos at a time - in fact, they're using some very simple but clever tricks to get the desired effect.
note: Brandon has left Epic Games since we talked with him at E3. He's headed over to 3DRealms to work on Duke Forever now - ed