Spear of destiny is a wolf3d game.
Some textures are flickering and are
changing to rectangles for a short
periods of time. In wolf3d this happens
too, but only in some places, while in
Spear it happens right at the beginning
of the game, so easy to reproduce and see.
This doesn't happen under dosbox, and
I mostly sure this didn't happen on 32bit
machine under dosemu, so I attribute
the problem to cpuemu.