I just got it from the App Store, and it plays just like Dead Space on consoles.  No on-rail shooter bullshit.  The controls are surprisingly fluid, graphics are better than a PSP/Wii game, and the sound is just as good as consoles when playing with headphones. 
 
And yes, the game is scary as fuck.   
 
Here's some shots I took from my iPhone 4.  I have no idea how it'll run on a 3GS, but I can say to not try this on a 3G...and if you are on a 3G, upgrade already damnit.   
 
Check it out, and I bet you guys will be surprised. 
 
   

Gallery

Do your hands still cover half the screen and do you still have no feedback as to how far you can move your fingers before the virtual joystick can't register it?

I agree, the iPhone 3G is a piece of shit.

Is it coming to Android or Windows Phone 7?

It's actually only cosmetically Dead Space.  In reality, it plays like warmed up arse.  The engine is well used though;  realtime shadows, bump maps, specularity and lots of alpha in effect.

  No on-rail shooter bullshit. 

Yeah, it's pretty good. The graphics are nice, the controls are pretty good, and the game plays well. 
 
Two problems though: 
It's too easy to switch to the weapon's alternative fire 
Not quite enough power nodes or credits, probably so you'll buy them with micro-transactions 
 
Well worth the price of admission though.

"

  No on-rail shooter bullshit. 

And yet Extraction is still better than this.  But have fun with your tech demo, I guess. "

Should I bother trying this with my 3GS?

Oh, KaosAngel.  Never lose your exuberance.

I still haven't purchased this, merely because I can't decide between the iPad and iPhone version. Why couldn't this just be a universal app. So stupid.  Basically, they're making me pick between platforms, and I'm picking none of them. Nice business move, EA. 

I dunno, looks a little too sideways for my tastes.

" I dunno, looks a little too sideways for my tastes. "

I would love to get this... but I have decided to steer away from virtual d-pads and shit like that... It doesn't seem like the type of game for the iPhone...

This is the first iWhatever game I've taken seriously (that's not to say it's good)
It still looks like a shit to play

" This is the first iWhatever game I've taken seriously (that's not to say it's good) It still looks like a shit to play "

Just purchased it. I want my money back.

" @MegaGoat said:

" This is the first iWhatever game I've taken seriously (that's not to say it's good) It still looks like a shit to play "

What does that even mean? I have heard good things about this game, but I'm not sure if I wanna spend that much money to play it. "

" Do your hands still cover half the screen and do you still have no feedback as to how far you can move your fingers before the virtual joystick can't register it? "

" @ProfessorEss said:

" I dunno, looks a little too sideways for my tastes. "

Yeah, it seems like it would be really hard to play like that. "

" I would love to get this... but I have decided to steer away from virtual d-pads and shit like that... It doesn't seem like the type of game for the iPhone... "

" @KaosAngel: how long is the game? "

" Should I bother trying this with my 3GS? "

What does that even mean? I have heard good things about this game, but I'm not sure if I wanna spend that much money to play it. "

" @ISuperGamerI said:

What does that even mean? I have heard good things about this game, but I'm not sure if I wanna spend that much money to play it. "

It means play it. I beat it and it's a pretty good game. I found it worth my $7. "

" @awesomeusername said:

" @ISuperGamerI said:

What does that even mean? I have heard good things about this game, but I'm not sure if I wanna spend that much money to play it. "

It means play it. I beat it and it's a pretty good game. I found it worth my $7. "

I actually just saw my friend play this game earlier on his iPhone4 and it looked sweet. There are even achievements that you can unlock. "

I was also quite skeptical about the playability of a 3rd Person Shooter on a touch based device, but after researching via videos and reviews I decided to take the plunge.  Considering that this is the most I have ever shelled out for an app, this definitely qualifies as a fairly "big" leap for me. 
 
I'm not at all disappointed with my purchase of this game.  The controls are fine, the action is enjoyable, and the game looks and sounds great.  It feels like a very worthwhile part of the Dead Space universe and the integration with the main story is quite rewarding. 
 
All in all, I highly recommend it. 
 
Oh, and I have a 3GS and the game works fine!

Nobody actually thinks Dead Space games are scary, do they? If so, give me a break. What the fuck is wrong with you?

he  called it an iPhone 4g......haha

its a shit to play indeed - my opinion of course.  also its got a nice frame rate but looks like quake 2.