The game can be launched and the demo played, however it lacks the control interface... without keyboard, one will have to be find another way to play...
For the NES emulator, they designed a virtual gamepad:
Developers of Doom on iPhone are currently thinking to all type of ways to provide the control interface, and why not the 3D sensors located in the iPhone? If you see in the street a guy using his iPhone as the Wii remote he might be using the last version of control interface of Doom on iPhone.
