It came to my attention that some changes and bug fixes were needed in Doom for iPhone and iPod Touch. I have implemented these changes in the new Doom v1.1.0 available on Cydia in the Games section.
New in v1.1.0:
Added a rudimentary change weapon button to replace the unneeded top left turn button. The button simply rotates through each weapon (1 through up to 9). It currently is not a "next weapon" button as it attempts to switch to that weapon slot, and not the next slot with a loaded weapon.
Fixed the movement speed to match Doom for the PC. The game can now be played much easier as it was moving too fast before.
Fixed the saving & loading of games. Games are currently saved to /Applications/Doom.app/saves/
Fixed the lack of a backwards motion. Now if you tilt the device down, it moves backwards, as intended.
Fixed the lack of speed settings. Now based on how far you tilt the device, the speed key gets enabled.
That's all for now. Whew! Keep the feedback coming!