I ran the game with the glide wrapper, but having read all this information, I edited the config so that it now runs in direct 3D.
The Direct 3D rendering is much nicer, due to the better quality of the light halos. Everything looks very crisp and clear, the unreal engine is a really beautiful, classic FPS engine IMO.
I use an Nvidia card, as such I went into the NVidia control panel and set up anti aliasing for this game, there are no jagged edges as a result.
Having played many classic FPS games since Wolfenstien 3D onwards, I have to say that this is one of my favourites. It is similar to games like Blood or Realms of the Haunting, but the unreal engine makes it far more satisfying to play through, due to the variety and solid feel to the combat in the game. In particular, the boss fights have been extremely memorable and satisfying.
One of the most impressive parts of this game is the design and feel of the levels. The textures are not hi - res, but they are very well done and everything looks amazing, due to the time and skill that was obviously lavished on making it perfect. The mansion interior is perfectly gloomy and really captures the imagination.
People forget that 3dfx stopped GLIDE development 16 years ago, and had officially transitioned to D3d before the company went under. Yes, the D3d version looks very nice in my system (Win10x64, R9380 4GB, Crimson 16.3), and all of the original GLIDE effects render fine under D3d these days (D3d surpassed GLIDE in supported effects years ago) and I actually think it looks substantially better than GLIDE looked on my old 3dfx cards. When the game originally shipped, the better experience was definitely the GLIDE version, but that hasn't been the case for a number of years, now, for the obvious reasons--volumetrics and other effects are no problem at all in D3d today.