The main problem with Doomsday is that it's WAD compatibility is meh, so make sure to keep a copy of GZDoom and Zandronum on hand. Things you might find worth looking up in modland for modern FPS-nes, though you'll need (G)ZDoom to get these working:
Smooth Doom: If the snap animation of the shotgun isn't for you, this makes everything... well, smoother without altering any gameplay. Also comes with minor variety boosters like enemy skin variants. I would however recommend looking up the weapon and monster only versions too, because you can't turn these off in vanilla. Obviously, Smooth Doom with everything doesn't work out when custom monsters or weapons are in the house.
Project MSX: Modern FPS is written all over this, everything you could possibly want without the bullshit. Hasn't been updated in a while though. There's a thing called MSfiX'd for the modern GZDoom, but it's in beta.
Metadoom: Doom game content from every game, thrown together into a blender and done in a way that doesn't explode the game. It takes a while for new stuff to pop up, but when it does things get really interesting. Megawads are required for this.
DoomRL Arsenal: OK so you've come in from Tower of Guns or Ziggurat. This is for you. Grab the last plain ZDoom update for this though until it eventually its updated (long wait for releases is Doom life, live it.) Pump this into WADs you've played before for a whole new way to enjoy them, or in Oblige generated maps for that extra roguelike flavor.
DoomRPG: This thing is kinda dead so I can't guarantee anything for the latest GZDoom, but if you're wondering what Doom was like with RPG elements mixed in... here you go. No, not the mobile game.
HXRTC: Lots of guns? Check. Lots of monsters? Check. New decorations with a purpose that can even shoot at you? Check. Shops? Check. Killing a zombieman in a tank with money and spit? Check. This is almost too random and chock-full sometimes as well as sometimes not being as thought out or consistent as DoomRLA, but that's part of the fun. Also it's updated very regularly so latest stable sourceport isn't a problem. Recommended to run on harder WADs or Oblige.
Hideous Destructor: Don't play this unless you have some experience under your belt, but it's basically Doom through the eyes of regular Joe Marine instead of Doomguy. Good luck surviving, physics is looking to kill you alone. This quality can also make a few WADs unwinnable, so keep that in mind.
Beautiful Hell: MMO-style color tier randomizer for monsters. Works with most weapon mods.
Complex Doom/All Out War 2/whatever: pick this up to save a download in multiplayer severs. If you're looking to play it like this odds are you'll be running around servers running this most of the time.
Death Foretold: This has been also popping up on multiplayer, but it's not bad in Singleplayer either. This is basically a Doom 4 weapons mod without the fat and focusing on speed. Excellent for run-and-gun, just make sure to use a map that isn't completely broken with double-jump.
Post edited May 24, 2017 by Projectsonic