Just yesterday, the mapper DMPhobus released the first alpha version of his masterpiece Darkmoon. It is a modern interpretation of Doom's original "Shores of Hell" episode, heavily inspired by Doom 3, Doom 64 and PSX Doom, taking place on Deimos. It aims to be a more serious and semi realistic doom mod, without sacrificing the fast paced gameplay we all know and love from Doom. It also aims to be a replayable mod, every map has 2 different exits meaning each playthrough will lead you thru a different set of map. More info and a download can be found here.