Let me start by saying that I never in a million years would have thought that BioShock -- one of the most atmospheric and gorgeous shooters I've ever played on console and PC -- would ever make its way to iOS. The fact that it exists at all is an achievement, and while I'm about to sort of tear it apart before your eyes, 2K and Take-Two deserve a lot of credit for having the guts to try it.
That said, it's not great. It's not even "good" most of the time.
If it had never been released on any other platform, I might feel differently. It might be easier to overlook the many things that are very, very wrong with it and see it as an exciting new IP. But it's not a new IP, and unfortunately this is the worst version of it you could possibly choose to play.
The visuals suffer tremendously in the move to iOS. Textures are super blurry and pixelated, character models are stiff and ugly, and any kind of special visual effect like fire, sparks, or electricity looks cheap and cheesy. In short, it's nothing like the past versions of the game, even on the lowly Xbox 360.
The opening scene, which sets the stage for the entire rest of the game, was plagued with weird graphical glitches, flat black textures that stood out like sore thumbs, and odd lag that caused the camera to jerk around. At several points during the story, characters got stuck in doorways, debris on the floor and walls disappeared and then reappeared, and objects shook violently as they interacted with other pieces of the game world. It's not pretty.
I honestly don't know if the lackluster visuals and glitches are simply due to a poor porting job -- which is entirely possible -- the limits of the hardware itself, or the constraints of fitting a game this big into an app that meets Apple's limits for size. Whatever the case, it's a very rough-looking game, and when visuals impact the atmosphere as much as they do in BioShock, that alone is a deal-breaker.
In terms of audio, it's a faithful reproduction of the original, and the retro tunes and voice acting that everyone loves remains intact. It's obviously a much better experience if you equip a pair of headphones, but that's just part of mobile gaming these days.
Then there's the controls. First person shooters on touchscreens are inherently at a disadvantage, because this genre of game requires precise movements and physical feedback. That's just the way it is. The touchscreen controls in BioShock are adequate for moving around the world, but the fact that you can't aim your weapon and fire at the same time without lifting your finger makes combat feel odd and clunky. As does the plethora of tiny buttons that pop up when interacting with objects in the game world.
Playing the game with an MFi controller helps out a great deal, and the SteelSeries Stratus felt particularly comfortable. There's no input lag, which is a big deal, and being able to search objects with a single button press -- and of course shoot while aiming -- is a huge bonus.
In the end, this is BioShock crammed, cut, and wedged onto iOS. It's the full story, and all the amazing characters are still there, but as I mention above, this is quite literally the worst way you could choose to play the game.
If you absolutely have no other way to enjoy BioShock -- that means no capable computer, no Xbox 360, and no PlayStation 3 -- and you're never planning on getting one... ok, play it on iOS. But if there's even a sliver of a chance that you'll one day be able to play the game as it was meant to be played, please save yourself the $14.99 cost of the iOS version and enjoy it some other way. You'll be glad you did.