There is a huge difference between the screen technology being displayed in technical demos and the final released product. (goodereader.com)
Still Games has released a short technical demo of Animal Gods which is available for Windows and Mac, which you can find the links for these respective builds below. (thatvideogameblog.com)
Epic has created some great technical demos for their engines, Samaritan, Infiltrator and Elemental, it would be great if we saw a game that took place in any of these universes, but maybe that's wishful thinking... (playstationing.com)