Someone called Zogrim on YouTube made a neat video showing the differences between Nvidia PhysX on and off on Metro: Last Light. Check inside for more details and the awesome video.
This was shared by Nvidia on their official Facebook page and the video above shows some of the neat differences in Metro: Last Light when you enable Advanced PhysX (powered by Nvidia). For those unaware as to what PhysX is, it is a simulation technology currently in the hands of Nvidia whom is also always developing it further and making it more advanced. This technology is only usable on Nvidia cards though, so those with an AMD card will have to miss out on these features in Metro: Last Light.
So yeah, check out the video and be wow-ed by the awesome graphics in Metro: Last Light, which only become even more awesome when Advanced PhysX is turned on!