Currently, the rumor is that Guerrilla Games is cranking away on Killzone 4 and a mysterious new IP.
It's unfortunate that the developer wasn't at E3 (the most glaring omission of Sony's press conference in our estimation), but at least we get a new hint thanks to a recent job listing for a Senior Game Designer (as spotted by PlayStation LifeStyle ).
The listing says they want you to apply if "you've worked on (and completed) one or more FPS/action games as a Senior Game Designer," which basically implies that the new title in question is a shooter. But then there's the part where they put a heavy emphasis on online multiplayer, saying they " really want to hear from you if you have an extensive knowledge of and affinity for Online/Multiplayer design." The implication there is interesting…it could just be talking about a standard multiplayer mode but the way it's written, it almost sounds like a MMOFPS or something that puts multiplayer before single-player.
Oh, maybe I'm just being paranoid. I hate the idea of not having a campaign, so I could be looking for fire where there is no smoke. At the very least, Guerrilla is working on something and gamers everywhere would like a peek. Soon.