I have some reasons:
- *arguably* the best console graphics to date
- ps3 exclusive
- expected to be a AAA game (and is delievering with a metacritic average of 95 so far)
- deep multiplayer component that could possibly turn into one of the most played online games on ps3.
- Add to that future DLC content including more maps, possible co-op and more
- related to the 'ps3 exclusive' point, it's an exclusive SHOOTER for the ps3 - a genre that isn't particularly well represented on the ps3.
- (semi) destructible environments
- intense and hectic single player campaign (at least from what I've inferred from all the video footage of the game)
- it's been a long time coming...this game was shown way way back and it's finally going to be released
*big point* It actually meets or at times exceeds the footage shown in that infamous trailer.
*big point* shows the graphical capacity of the ps3, which leads to the next question. How much can GG or other ps3 developers improve on the graphics shown in killzone 2?
- ps3 owners excited over all of the above points and snowballing the hype.
Those are at least the things that I see contributing to the hype of the game.