The only good aplication of multiplayer on this game i can think of would be for a mod where you are the MTF. Basically a competition to find and kill the D-class we usually are while evading the uncontained scp items, starting from gate b. Yes, it would take nearly all of the fear, but I could see its appeal.

But probably the work required would be staggering.

Does Blitz3d even support network multiplayer?

Yup. There are shooters with multiplayer made in Blitz

Itz wouldszez notz workesewz