When do platform differences warrant separate pages?

I see that Prince of Persia: The Forgotten Sands for Nintendo DS doesn't have its own page even though it's completely different from the console versions, while The Legend of Zelda: Ocarina of Time 3D, which is essentially just Ocarina of Time with a graphical makeover and some minor mechanical differences, does have its own page, and I'm not sure what the rules are.

So what exactly is it that determines whether different versions of a game should have separate pages?

I think it's the title, and that alone. If the game company wants it to be viewed as the same product or a different one is what counts it seems. I'm not saying whether that's right or wrong though.

@Gwendolyn: Very true, but my point that the game company wanted them to be viewed as different products is the important part and they are seen as different products.

Title has little to do with it. The main question is if the game is substantially different between platforms or releases in a demonstrable way, such as through additional content.

@Hailinel: I don't think that's quite right either, as NDS releases of games on other systems which are released on the same day are on the same page here on GB, yet they're entirely different. E.g. PES 2008. The game is completely different apart from being about polygonal football game play. The reason it's on the same page is because it was marketed as a single product across multiple platforms, despite the games not being similar. (I've had the xbox 360 version and the DS version if you needed to know)

I think it's usually handled on a case by case basis, although @Hailinel: put it best when he said that the content has to be noticeably different from the other versions.

There doesn't seem to be a consensus here, so it would be nice if a moderator could chime in with an authoritative judgment.

It's handled specifically by game. They look at all of the parts of a game and then decide if it needs its own page or if it should be attached.