[Dysiode]

A touch interface, for one. Emulates are find and all but I find their inaccuracy frustrating more often than not. Further, it's not just a 20 year old game on an emulator. Somebody has to port it, make graphics (for what they are worth), probably localize it. Sure it's not necessarily as hard as making a game from scratch (though that could be debated), but that doesn't mean the costs aren't similar.

[Adirael]

Are they actually ported? I've played Sonic games on iOS that were just emulators (awfully done emulators).

[pawn]

I have Final Fantasy 1 for my Nokia, and it's actually a port rather than an emulation. I haven't looked up the differences, but what I've found so far are: The interface supports tapping on characters rather than selecting them with the 'directional-pad' which appears on the map when walking around. There's at least one new area to explore. The magic system is more like later games, using MP. Graphics have been improved

I'm not sure how many of these are ports from the DS version, though. Possibly all of them.

Based on the screenshots of FF3 for Windows, it appears to be a port of the DS re-make rather than the Famicom original

[e_proxus]

I think they're mostly just ported. I've bought a few of the Square games on iOS and they were just the normal games with touch capabilities added on top of the old menus. No usability changes at all to accomodate modern touch patterns. There are many "click" needed to navigate some menus, which would just have been one touch or drag in a modern app. Scrolling was also laggy and glitchy.