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The game doesn't look right.
Workaround. On some early Radeon 9 series cards, like the Radeon 9000, 9200 and 9250, if you go into Poison Time, the screen blacks out. We are working with ATI on a fix, but in the meantime, if you set your launch options to include "-dxlevel 70", the Poison Time effect will not cause your screen to black out.