Maybe you've heard about
Doom RPG, a game concept John Carmack whipped up when he was given a phone that had a full-colour screen back in the days before smartphones were a thing. Naturally he started tinkering to see what sort of games could be programmed to run, with the result being a turn-based take on id Software's Doom called Doom RPG.
A game played from the first-person perspective where you talk to scientists, read terminals, put out fires, and attack all manner of monsters. Working with Fountainhead Entertainment, Carmack and id released Doom RPG for mobile phones back in September 2005 - a time when mobile gaming was still a relatively new concept. Or, tied to the idea of playing Snake on a Nokia brick.
Anyway, unless you had it lying around on an ancient phone Doom RPG was ultimately left to the history books as an interesting off-shoot to the iconic FPS franchise.
That is of course, until now. With a
fully working port of Doom RPG available to play on PC. To get it running you'll need to do some
Archive.org sleuthing to get the original files for the game, but it's a fairly straight-forward process. What wasn't straight-forward was the port itself, which required reverse engineering of the game by dedicated Doom historians at GEC.inc. This has been years in the making.