I am trying to play Ion Fury with the software renderer option; however, if I select it the game will always open to a black screen where the sound plays and the game seems to be responsive albeit unplayable.

I have attempted to simply swap from "OpenGL" to "Classic" while in game after opening with the the OGL renderered but this does not seem to actually do anything. The game still appears to be rendering with OpenGL when I change it this way.

I much prefer the look of the software renderer so simply playing with OGL is not really an option for me.

I've had the black screen issue on an older laptop. I'm not sure you have the same issue.

However if the game runs in OpenGL mode, you can simulate certain things that come as part of Classic/Software rendering mode:

r_yshearing 1 - this will turn on the "Y-Shearing" up/down look of Classic/Software rendering, and also the sprites won't be paper-thin when looking up/down, they will always face your view.

r_shadeinterpolate 0 - this disables the shading/banding interpolation and makes it look closer to the Classic/Software rendering.

I play this way in OpenGL mode, because it gives more FPS. Even on some modern fast CPUs, the Software rendering has some FPS drops in visual-heavy areas in high resolutions.

This is off topic but those two commands you just posted completely solved the issues I was having with the game.

One was some white pixels showing in some of the surfaces, especially in dark tunnels.

The other was when I looked all the way down or up the game would bug out and textures will start clipping.

Doing what you said fixed the issues! It was driving me crazy because the only solution for both problems was switch to software and dropping frames in the more hectic parts of the game.