Metro: Last Light is to be released by new publisher Deep Silver on the 14th May (Americans) and for the rest of us, on the 17th May 2013!
The game was originally slated for a March release, but after the rights to Metro: Last Light were sold to Koch Media in the THQ assets auction, some delays were inevitable.
The 4a Games team have said that the extra time will go towards final polishing of the game. Pre-order details are also still being worked on after the change of publisher.