There's no question that the appearance of Epic and Chair's Project Sword was the second biggest surprise of Apple's Autumn event.

It was only trumped by the arrival of the Epic Citadel app; a technology demo based on the (or a?) Project Sword level that you can walk around.

Cookin' good lookin'

Perhaps only ranking alongside id Software's id Tech 5 Rage engine demo at QuakeCon, the quality of the Unreal Engine 3-powered content was very impressive, even taking into account the empty, walk through nature of the experience and its restrictions, requiring iPad or 3GS or better hardware.

Throw into the ring the detail that developers can get their hands on Unreal for free, paying $99 for a release licence when their game's out, and then paying 25 percent in royalties after their first $5,000 in sales, and you'd think life couldn't get much better for them.

Compare and contrast

Yet, with great power comes great responsibility.

Most obvious is that Epic Citadel is the product of a small team of highly experienced Epic artists and coders over eight weeks.

Okay, it's not a long period of time, but these are the pinnacle of Unreal developers. It's unlikely the likes of EA Mobile or Gameloft have teams that could match them in terms of getting the most out of Unreal.

Drop down a level, the small studios currently doing good work with middleware such as the Unity engine, let alone one and two-man bands, will struggle making the transition to this quality of art production.

The curse of 3D

In that respect, people with Unreal experience will no doubt put together new teams and studios to make iPhone games - and new blood is always exciting.

But it's hard to see the additional cost of development, combined with the quality of rival Unreal games from the likes of Square Enix, EA and Gameloft - not to mention all the current Unreal licensees on console who will come piling onto the App Store - making the commercial playfield any easier than it currently is.

Certainly I can see that Unreal could scale well for mid-sized studios with 3D experience such as Rovio, Digital Legends, RedLynx, Polarbit, Fishlabs etc. It's much harder to make the case for outfits with less than ten staff though.

And, don't forget, Unreal has implications for the types of games released too.

We're still in a situation where it's the quirkly, cheap, often 2D games such as Doodle Jump, Pocket God, Angry Birds, Cannabalt, Super Mega Worm, Flight Control, Osmos and Plunderland that excite, and have defined, the iOS audience.

So sure, there will be some amazing and appropriately priced Unreal-powered games, but as the gap between games for iOS devices and those for XBLA and PSN narrows, as something is gained, something is also lost.