"I think the most immediate thing people notice is the leap in visual fidelity. We have more horsepower with PlayStation 4 and that means you can do bigger, bolder things. It’s running at 1080p, it’s running far above 30 frames – we’re aiming at 60 – so that’s a very good thing. That’s the first thing people notice just the visuals, the way it feels."

While the remainder of the story talks about multiplayer, they've already confirmed that multiplayer will be running at 60fps.  So assuming this is single player.  Far above 30fps also sounds to be at minimum 45fps.  Hopefully they get 60fps, but if it's a locked 40+ then I don't think anyone will complain. Well.  I do think people will complain, just no one interested in a PS4.  You guys should just hope it's locked framerate and not unlocked, because then you'll start to notice framerate changes while you play.

http://www.playstationlifestyle.net/2013/09/10/killzone-shadow-fall-on-ps4-is-running-far-above-30-frames-the-1500-challenges-at-launch-are-just-the-beginning/

I never understood why it has to be 30 or 60 frames.  Why can't games run at 45 frames?

Edit: nvm shoulda finished reading...

Because 60 looks like how a crisp apple taste like.

It's better at 30 or 60 because the refresh cycles that a modern HDTV has....it will look off if the framerate isn't a divisor or 30 I believe.

The "feel" of 60fps.

The reason 30fps is what most devs aim for is that while you can notice it, it still looks somewhat smooth. 40fps and up will look smooth to most people. Supposedly though there's no one that can visually tell the difference between 60fps and up, although higher framerate, even beyond 60fps is still good since it'll react better to what your input was. You might not notice the difference, but it's there.

"30fps but feels like 60."   -Ninja Theory talking about DmC.

As long as the MP is 60 FPS they should be good. That's where it really counts. I'm amazed at the visual fidelity they showed even on MP while running at 60. SP could be at 30 and they could add in more visual flare if they liked.

It's easy to see 120 vs 60 lol. Heck it's even possible to see 240 vs 120. Just track an object as it moves across the screen. You will see stutter.

Can't wait for this 60 fps madness to go away. Overrated, overhyped, over-everything. Is it noticeable? sure. Is it cool to have? Yup. Is it important? NO.

I'm only saying what I've heard.  I've never played a 60fps game that didn't look smooth without testing it myself to try and make it not look as such, so I assumed they were correct.

Come to think, I'm also not sure what platformers run on my PC, but I don't think I've seen any stutter when playing a game  like Super Meat Boy running across the screen as fast as he does.