system shock 2 had rubbish graphics even when it was released. the reason it is regarded so highly is due to story/mood. just like bioshock.
And plot, and non-linear mapping. Bioshock seems like it will be pretty heavy on plot, but if that demo is anything to go by then it will be as linear as all hell.
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"That don't look like no golden marmoset I ever seen!"
Steam + PSN: PHJF