It looks like 3Dfx will be required, but in any event the game won't be out till maybe the fall. Another potential disappointment is that there won't be any real land masses in the game - the engine in its current state just can't handle it. Volume two will probably have it, though. The maps are still hand-painted, but there will be some provision for users to create their own scenarios. A few other things are being supported, like transparent menus, unit development, research, and the like.
Some weapons literally have the ability to shoot across the map.
Two campaigns will be included. At least it tackles some relatively new subject matter. It should be out this summer. The next Warhammer 40,000 game will be Chaos Gate, developed by the guys at Random Games. Imagine Soldiers at War but with space marines, and you'll pretty much get the picture of how Chaos Gate will work.