NeoGAFs Kent Brockman
As spotted by PCGamesN, a modder called Dithered Output has been working for around two years on a new add-on for Doom called "Siren." Releasing a trailer back in 2020, with a demo being available to play on the creator's Itch.io page. What makes this mod stand out is that it changes the game to such an extent that it almost doesn't look like a standard Doom game. In fact, it looks almost like something fans would see in an Aliens adaptation, which includes rooms full of Xenomorph-style eggs.
Set on Redark 1979, which the download page describes as a habitat beneath Mars' Mythos ocean, the visuals are a far cry from the graphics of the original titles, though it still obviously has the blocky aesthetic that is associated with many Doom 'clones' from the 90s. The trailer suggests a non-stop fury of sci-fi action with a kind of survival horror vibe to it, not a million miles from James Cameron's 1987 classic action shooter. In general, it looks like it will be a high-octane add-on that seems to stand up as a game in its own right.
Those who wish to play it will need to download the Siren demo, as well as have a copy of either Doom 2 or Final Doom. They'll also need to have GZDoom which in itself has been used to make games like P.T. in Doom-style graphics. For now, there doesn't appear to be any mention of when the final mod will be coming out in full.