If you are an iPhone gamer and haven't tried Epic Citadel yet, you're doing yourself a disservice. Epic Games wowed the crowd at the recent Apple event with the free demo, showing an astoundingly beautiful virtual town running in full 3D graphics on the iPhone and the iPad. Epic's Mark Rein is here at GDC Online 2010 this week to talk to developers about Unreal Engine 3 on iOS and other platforms (he can't keep from showing off the game running on Android, even when you tell him that you work for an Apple blog and don't write about Android anyway), and I cornered him to chat about Epic Citadel and Project Sword, the game it's serving as a demo for.