This game is a timeless classic. It was truly innovative for it's time: cinematic storytelling, no user interface on the screen, context-related actions. Its main strength is however the amazing atmosphere that oozes out of every pixel. It simply is a beautiful game; the movements, the colours, the amazing music and sounds; everything just comes together perfectly. It has the real chemistry that every real developer aims for, and which has been painfully absent in a lot of modern productions.
The high-resolution version was already available on Eric Chahi's site. Good to see that GoG is selling this as well, plus some extra goodies.