Since the first games appeared in Apple's app store, the iPhone and iPod Touch have been eating away at dedicated handhelds' market share in mobile gaming. With the convenience of being able to play great-looking games on a smartphone, not only were more people playing games, but those people were playing games on the iPhone at the expense of Nintendo and Sony's portable consoles. But a contingent of "core" gamers would not be swayed so easily--the lack of physical buttons on the iPhone made it an inferior platform for "traditional" console games. Simulating those buttons on a touchscreen (or the use of capacitive accessories) was a stopgap measure, often implemented poorly. And while developers eventually figured out how to make excellent games that suit touch, accelerometer, and gyroscope controls, there hasn't been a good solution for the kind of side-scrollers or platformers that we loved on the DS and PSP. Mario beats endless runners any day of the week.
iOS games could benefit from physical controls. But be careful what you wish for, because you might get just it.
Last fall's iOS 7 introduced a MFi (Made for iPhone) specification for certifying hardware controls for iOS games. That meant accessory makers could create gamepads and cases with thumbsticks, buttons, and triggers that would work with any MFi-enabled game, no proprietary Bluetooth connection or API required. Three MFi controllers have been announced so far, from Logitech, MOGA, and SteelSeries, and Logitech's PowerShell is the first one I've tested. And after a month playing games with it on my iPhone 5, I'm left unenthused about the prospect of bootstrapping hardware game controls for any iOS games at all.
The PowerShell works exactly as advertised: you get to have physical analog buttons for a variety of side-scrollers, adventure games, flight sims, and fighting games. But its problem isn't compatibility, it's one of ergonomics.
I'll quickly run down how the PowerShell works. It looks like a glorified iPhone case, and that's basically what it is. Your iPhone 5, iPhone 5S, or 5th gen iPod Touch slides horizontally into a cubby at the center of the controller, communicating to it through a Lightning connector. The fit of this housing is great--my iPhone 5 slotted in securely and never felt like it was in danger of falling out. The Lightning connector is on a hinge that makes plugging it in and disconnecting it very easy, too. The iPhone 5C is too big to fit into the slot, and iPod Touches require an included intermediate plastic casing before it can fit in the PowerShell.
Once the iOS device is docked in the slot, most of its physical controls and functions are still accessible. Volume buttons aren't obscured, speaker sound is routed toward you, and the power/sleep button can be depressed with small plastic switch. There's even a hole in the back of the PowerShell for the iPhone camera, which doubles as the way to eject the phone from the casing (by pushing it out from the back). The headphone port is still usable as well, but requires a clumsy audio cable dongle to access.
All of these design elements seems to support the idea that you're supposed to keep your iPhone in the PowerShell even when not playing games. The inclusion of a rechargeable 1500mAh battery (doubling the life of the iPhone 5) supports that notion, but it's not something I ever did in practice. The PowerShell is adds to the already significant length of the iPhone (or width, when oriented horizontally). It's too big to comfortably shove in any normal pants pocket, though would fit fine in a shoulder bag or purse. But it's not something I would take with me on a day trip without any bags, even if I was wearing a jacket with big pockets. This is an accessory I primarily used on the couch and in bed.
And for those gaming sessions, the PowerShell was serviceable, but not great. Meaning, like I said earlier, it worked just as advertised. In the App store, Apple doesn't distinguish which games are compatible with MFi accessories, but sends hardware partners a regular list of supported games. From what I was told, Logitech takes that list and runs them through their own certification, posting approved games on this page. The number of games totals 52 right now, up from about 40 a month ago--Logitech says they're adding about two with every update. This page doesn't let you sort by new releases or show recent additions, but Logitech assures me that it's a feature they're working on. I'm more concerned that the rate of new game additions, and hope that it picks up as developers get their hands on these MFi accessories for button implementation. I didn't test every game on the list, but singled out the ones I thought would be best served by physical controls.
A flight game like Air Wings, for example, could use the directional pad, but was still easier to control using its original gyro controls. The wider grip of the iPhone using the PowerShell did make it easier to tilt the phone for those kinds of games. Bastion, an isometric adventure game, made the best use of the buttons, and came close to giving the illusion that I was playing with an Xbox gamepad. The console port doesn't scale to the iPhone's screen size as well as it does on the iPad Air/Mini, but I had more success playing it with the PowerShell than with the on-screen controls on the iPad. This was the case with a side-scroller like Terraria as well, though I didn't like stretching my thumbs to tap the shortcuts and menus on the screen while gripping the sides of the PowerShell. Button responsiveness, resistance, and throw are all good, though the XABY buttons on the right of the controller are a little closer together than you'd fine on a full-size gamepad.
In terms of compatibility, a big issue was that games didn't change their user interfaces when plugged into the PowerShell. Maybe they can't make the distinction between physical and touch controls, or maybe developers just haven't implemented new UI for MFi mode. One theoretical advantage of having dedicated controls is that you don't need to obscure the screen with your fingers to play a game. But many games, like The King of Fighters would still display touch control overlays when plugged into the PowerShell. This isn't Logitech's fault, but doesn't inspire confidence in MFi implementation.
But ergonomics is really where PowerShell disappointed the most. It just wasn't comfortable to grip and hold for long periods of time--more than 15 minutes and the base of my thumb would feel sore. That's because there's no comfortable way to naturally grip the PowerShell. Ridges on the back of the controller indicate where your middle fingers should brace, but the controller didn't have a good place for my palms to cup while keeping thumbs on the buttons in a natural resting position. During tricky combat sequences in Bastion, for example, I would end up squeezing the PowerShell between my two index fingers to keep it firm. It wasn't comfortable.
The PowerShell makes me recognize that the idea of adding physical game controls to the iPhone isn't a no-brainer, even if the OS natively supports it. This is a tricky problem that can't simply be bootstrapped with an iPhone case sporting analog buttons. It's going to take both clever design on the hardware side to work around the existing form of the iPhone and developers on the software side making better use of MFi support. Right now, MFi controllers are iterative improvements over touch controls--still a workaround and not a new paradigm for iOS gaming.