Downloadable Upgrade
The game was originally intended to have downloadable content from Day 1, but due to technical difficulties, the Downloads promised were initially un-delivered. On May 30th, 2007 the free downloadable upgrade was released. The upgrade included two additions:
- Online multi-player support including two new multi-player maps and a new multi-player game mode.
- Chapter 5 of the single player campaign which concludes the game storyline.
As of 2011, the two DLC files are no longer available from the Killzone website. However, there are other sources on the web from where you can download the DLC. In June 2011 because of the "Welcome Back" operation, Guerrilla published again the DLC in US and EU version.
Read more about this topic: Killzone: Liberation