>ctrl+f>only two mentions of Doom RPG
Carmack wrote the engine (over a weekend, if I recall correctly. He said he decided to finally check out gaming on cell phones and found them incredibly lame so decided to make something himself) and it was clearly inspired by the type of predominantly Western classic first person dungeon crawler PC RPGs that Carmack had played back in the day. He said he decided to go with the style he did as a way to design within the limitations of the platform instead of making a shitty half assed platformer that plays like shit or whatever.
There were 5 using the engine. Doom RPG, Doom II RPG, Wolfenstein RPG and Orcs & Elves 1 and 2, an original traditional fantasy IP made for the engine.
You can find all the iD RPG games and an emulator to play them here. I run them on my Android phone with J2ME and it works great. There's an onscreen keypad for the buttons. If you want to play on PC just use the Windows version of J2ME Loader.
All the iD RPG games are in this archive:https://mega.nz/#!Y7AjEawA!Ta2RQuOC235v0wQoLtVR7HJoN7bsiawkujSlq8A1Da4
Also, Doom II RPG had an exclusive black and white comic book tie-in. You can read it here:https://imgur.com/a/slxE9or
Found this pic using Wayback Machine on the old official website for DOOM RPG.