I am using a Macbook Leopard 10.5.2 with 1/5 Gb ram. With Crossover half-life 2 works fine with tweaks in the launch etc:
Launch Options:
-console -heapsize 512000 -dxlevel 80 -width 1280 -height 800 -window -novid +cl_drawmonitors 0 +r_shadowrendertotexture 0 +r_WaterDrawReflection 0
But the shadowed textures look rainbow.
I haven't seen this problem mentioned anywhere else on this forum.