You'll get a nicely remastered 720p version of the game with better sound, post processing and trophies.
Sony is all about HD remasterings these days, and has just announced the latest in its series of titles that got a little bit of high definition love. 'Killzone HD,' which will be available on PSN October 23rd, has been brought up to 720p and 30 frames per second.
The game also supports a few more graphics features, like MSAA and filtering as well as what developer Guerrilla Games refers to as "higher quality" sound effects. And of course, trophy support will be included.
'Killzone HD' will be $15 when it launches.