[chiefsucker]

Platform coherence, but also look & feel come to my mind.

While the guidelines are what the word says, vague guidelines with a lot of room for interpretation, they don’t necessarily dictate any details. When you look at it from a more technical point of view, it’s harder to do something nonconforming with Apple’s frameworks than with 3rd party alternatives.

Games are a different thing. They are more like their own operating system within iOS and usually have their own quirks (to make them playful).