Originally Posted By byuu
Finally, one I can answer.

Sim Earth needs proper vertical mosaic support to work.

ok I'll look into it, if Kale does not beat me. it's strange though, since we have some vertical mosaic support, but it seems to be not enough

Originally Posted By Heretical_One
That looks like color addition/subtraction, Kale.

As a "quick test", try the pilot selection in UN Squadron. I suspect it is similar.

Suspected cause: color addition or subtraction with halving is not working rcorrectly (possibly only with 0,0,0 blends)

the same color addition/subtraction seem to work fine with other games, though. it might be some edge case, I dunno, or a different reason

in general, if you want to test the various graphical modes and effects, you can simply recompile MESS with SNES_DEBUG_LAYER 1 in snes.h

then you can start to turn on/off modes and BGs (and isolate single priorities) and to enable/disable color math, horizontal mosaic effects and window masks.

of course, if the math/window/mosaic is enabled at the wrong time due to bogus read/write of the cpu, then these debug commands might not help much