Recently I was chatting to fellow Eurogamer contributor and official Nicest Man In Games Journalism Christian Donlan about the important issues of the day. Opening with a discussion about Friz Freleng and Robert Palmer - like any good conversation should - the topic then turned to in-game buttons on iOS, and how some are much better than others, even though the interaction itself is no different.
We discussed the way you get a real 'feel' from apps when you press their icon; similarly, both of us felt the swiping motion to unlock an iDevice was somehow incredibly satisfying. We talked about a shared dislike of in-game buttons in titles like League of Evil, and then Chris said something that initially sounded really stupid, but turned out to be actually quite brilliant.
"The best single button-press on iOS is probably Canabalt," he said. "And there isn't a button. But it feels like one. And there's no sound. But you sort of hear it in your finger."
Hear it in your finger. We both laughed, but if there's a better way to describe that particular phenomenon, I haven't heard it. And if you're wondering where all this is going, then fear not, because I'm about to explain why it applies to Monkey Bump.
Monkey Bump is a game from PomPom, makers of Bliss Island and the Mutant Storm series. In it, you tap the screen to propel your simian avatar up a never-ending tree, collecting fruit along the way to keep his energy up. Run out of juice - which is easily done, as your meter depletes without a regular intake of Vitamin C, and when you're hit by marauding insects - and it's game over. Kissing the female monkeys coyly peeking out from the sides of the screen increases your score multiplier while collisions with falling coconuts drop it.
It's incredibly slight, but it works. And it works not because it's as wonderfully garish as anything PomPom has previously made. It's not because the fruit splats and squelches in a gratifyingly gooey way, and not because the monkey is simultaneously cute and unnerving like all the best monkeys are. It's not because of his endearingly excitable hoots whenever a female comes into view, either, or that the birds flapping in to obstruct your ascent tweet so vociferously that you'll swear you've temporarily wandered into an aviary.
It works because there isn't a button but it feels like there is. As you juggle the flappy-limbed fellow, there's somehow a tangible sensation of gently pressing a tiny bellows to nudge him upwards. It's a little bit like the handheld water games you had as a kid where you had to squeeze a rubber button to guide hoops over hooks, only it's more effortless here.
It's hard to pinpoint exactly how it manages to convey the sense of touching something more than just a flat screen. There's some kind of complex digital alchemy involved, a combination of precision and feedback. Here it's a white circle that expands outwards from each press, accompanied by a quiet huff of air.
Maybe it's more than that, and that's perhaps a discussion for another time. But whatever it is, like Canabalt and those other great iOS buttons that aren't really buttons, the most important thing about Monkey Bump is this: you can hear it in your finger.
App of the Day highlights interesting games we're playing on the Android, iPad, iPhone and Windows Phone 7 mobile platforms, including post-release updates. If you want to see a particular app featured, drop us a line or suggest it in the comments.