I've read all the advice on getting Blood to run with Glidos, and I was experiencing extreme slowdowns in frames. So I think I finally got it running well, on my system anyway.
Download the official 3dfx patch.
Create a .bat file and place it in your Blood folder, with the following info:

set BUILD_BRIGHTNESS=0.9
set BUILD_GAMMA=1.0
set BUILD_640x480=1
set BUILD_RESAMPLE=0
set BUILD_NOPAL=0
set BUILD_NOFOG=1
set BUILD_CONVTEXTURES=0
set BUILD_TRICOUNT=0
set BUILD_FPS=0
set BUILD_VERSION=1
set BUILD_MRED=200
set BUILD_MGREEN=200
set BUILD_MBLUE=255
3dfx.exe

Open your Blood .cfg file and have your screen width and height set at 800 X 600.
In the Glidos .ini include Blood and its location, and adjust to 1280 X 1024, forced texture smoothing, and full screen.
I also ran it with Vesa support.
Nice picture with smooth frame rate. I tried enabling mipmaps, which gave me an even better picture but the framerate dropped considerably.
I'm running with a Radeon8500 and Win98.
I hope that might help someone.