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What's the difference between this and the 2001 PC version? Well, besides the obvious direct-x 10 support.
From the official site:

Technical Upgrades:
-PC rendering improvements (anti-aliasing)
-PC resolution and aspect ratio support
-Enhancements to textures, lighting, and shadows
-Shadow and lighting improvements

Other Additions:
-Gamepad/controller support (along with keyboard)
-New difficulty level (Hard Mode)
-Enhancements to textures, lighting, and shadows
-Steam trading cards and achievements
-Option to toggle between English or original Japanese voices
Also, contrary to the old pc version, it doesn't require obscure voodoo rituals to actually work.