cass:the memory problem (zbuffer) is gfx memory! and not fast memory , so free up some gfx memory by turning off or down yer wb settings/patterns etc.
luckily i have a mediator with 16mb gfx mem so it wont dry out as fast as a cvision or a bvision BUT! there still is some issues though but not with this game

anyway i like trhe game alot and im on level 19 atm, nice feature that it saves level 1 by one ..
cheers