Gamewatcher reports that with a PS3-emulator Demon's Souls can now be played on a PC:

Demon's Souls is playable on PC for the first time

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Thanks to the work of this emulation team Demon's Souls, the PS3-only precursor to Dark Souls, can now be played on PC for the first time. You can see the results above, which is captured on a PC running a i7-6700 @ 4.0 ghz.

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Thanks Farflame!