Yes, BioShock doesn't look as good on iOS. It's the truth. In-game lighting and shadows are cut down pretty dramatically, as are art assets. The grandeur of Rapture is distinctly less grand, which sucks some of the life out of one of my personal favorites. The first thing you'll notice is "iOS fire." The game's opening -- a plane crash -- puts main character Jack in the ocean surrounded by some hideously ugly fire animations. It's the first hint that the iOS version of Rapture has been shrunken down to fit within Apple's app store file size limitation, and it's a nagging issue that I couldn't shake in my hands-on time.
But maybe you haven't played BioShock before and you're not overloaded with lofty expectations (like me). First things first, you're in for a treat! Second, even without my lofty expectations, you should probably play this on a couch with an Xbox 360. BioShock is a great example of world-building in video games, and the iOS experience is a subpar representation. Simply put, between the lessened scale and the delivery medium, BioShock iOS is distinctly less immersive.
The good news is that it plays perfectly fine, even with touch controls. Admittedly, the touch control situation is not ideal. Like Grand Theft Auto's mobile ports, virtual buttons appear contextually on screen. Also like Grand Theft Auto's mobile ports, I found myself scrambling to figure out which virtual button to push as a gang of enemies descended on me. "But Ben," you ask with a hint of hesitation in your voice. "Why not use a bluetooth controller?" Well, you can. And I tried that with a MOGA bluetooth controller. That totally works.
Here's the thing: I don't carry a bluetooth gamepad on me. Do you? Does anyone? Okay, does anyone who isn't a crazy person? You can play BioShock iOS with a gamepad. But will anyone?
In terms of nuts and bolts, BioShock iOS doesn't have any of the extra downloadable content that the console/PC version has. It requires a newer iOS device -- iPad Air, iPad Mini 2, iPad 4, iPhone 5S, iPhone 5C or iPhone 5 -- and straight up won't run on earlier devices (says 2K). It'll arrive sometime this summer at an unknown, "premium" price.