Yes, it is software based.
We can try to write an "autoexec.cfg" and write to it "r_picmip 0" in order to bring more detailed textures.
EDIT:
Probably I located a minor problem in this release of Hexen 2 for GCW Zero.
At gameplay there are some sounds that are loaded on demand (the first time you pick up a quartz flask, some enemies sounds...) the game stops working and rendering while the sound is being loaded; but after half-hour of good gameplay; at "Barbican" stage, I drop into castle moat, where there is a small octopus, I hit it... and the game stops (probably loading a sound) but the engine never recovers from this on demand loading, GCW Zero crashes to black...
...and a new rom flashing needed, hahaha, sincerely I don?t know how many times my Zero has been flashed.
I think these loading on demand can be avoided loading the entire game into RAM, we have 500+ MB and the entire game takes around 150 or 200