Bungie open sourced the Marathon 2 engine quite a long time ago so you can download the entire trilogy to play right now on Mac, Windows or Linux.
The only thing better than Marathon was multiplayer Marathon. I can still hear the SPNKR rockets flying past. It was right up there with multiplayer GoldenEye.
Doom was hot on the heels of Wolf3D’s success. And the first third of the game was free shareware.
Duke 3D had attitude yet wasn’t completely crass (Duke Forever). Yeah there were strippers and shit, yet… Seriously Duke Forever, what a load of rectal drippings… Anyway, also had a free shareware version.
I think that’s a key thing, the free shareware versions, really a great way to market the games. Granted if they’d sucked it wouldn’t have helped, but I do think it’s a big part of why they were successful.
Thanks for the update. I had played around with the open source engine some years back, but I seem to remember that it didn’t include the original game content at that time. (I actually do still have my original disks somewhere, though.)
You forgot the other best part of multiplayer Marathon: low-gravity maps where a hit with a grenade or a missile sent your enemy flying across the map.
I still play Duke Nukem 3D on my PC. Simple controls and hundreds of maps. 
That makes me wonder: Rainbow Six and Counterstrike do share a good amount, yet I hazard to say that many of the people who liked Doom & Duke also liked the original Rainbow 6 and that was not the same kind of gameplay at all as Doom & Duke.
And, for third-person, Saints Row & Just Cause.
Here’s an article that nails most of the points.
Most modern military-style FPS games are slow and have limited numbers of weapons, environments, and enemies. You kill people or other human sized targets (e.g. maybe a mech), maybe blow up a tank or a helicopter every once in awhile, and they’re mostly linear and story based. Pretty much the direct opposite of Doom and its predecessors where you run and kill fast, like Serious Sam, Pain Killer, or Killing Floor.
The most fun Doom moments for me are running around medium to large sized areas corralling a huge swarm of demons and dodging all their projectiles. It makes you feel powerful. It does take some skill, but it’s not particularly demanding either, so it’s easy to slip into a gamer trance.
Did you see the Doom 4 trailers? It didn’t seem to have much of any of that.
Although it’s not an FPS, for similar reasons I’ve also greatly enjoyed the Binding of Isaac series.
Agree with the points so far.
I think the scary, but nonetheless open and colorful levels is a big part. More modern games are either just based in the real world, or try too hard to be dark or gritty. Doom compares well to either of these options.
I wonder also about the absence of a sniper rifle type weapon.
Don’t get me wrong: I love sniping enemies, and that’s probably why pretty much every FPS has them. But in some ways they preclude the kind of level design and run and dodge gameplay that you get in Doom.
I’ve seen that image before, but is the map on the right an actual literal map from a real game? Which one?
I’ve noticed that that part. Whether it’s CoD and its clones or Gears of War*, they try to be dark or gritty and use a lot of desaturated grey and brown but their darkness and grittiness is immature. Hotline Miami and Not a hero are a lot darker and grittier than CoD or GoW. The grit in Cod or GoW is sanitized like they would be in a PG-13 summer action blockbuster or a Fox-approved war movie.
It’s like they saw the movie Saving Private Ryan (which used desaturated grey & brown to good effect) and fixed on the most superficial aspects.
The only level from CoD that’s arguably dark & gritty is this one if you look at it the right way:
*Not based in the real world but quite similar in other respects.
Was I the only one that got turned on to Rise of the Triad by looking for games similar to Doom? What a blast that was.
Wasn’t the demo on the Duke 3D CD? I never bought the full game but that demo was a blast.
It’s nowhere near ‘new’ now, but Serious Sam is the closest thing to a modern inheritor of the Doom legacy; It’s absurd, has huge open areas full of jillions of crazy monsters, features a bunch of hilarious and over the top weapons, and is all about running around like a madman shooting stuff. Strongly recommended.
Yeah, I would tend to say that Serious Sam was like a little brother to Duke Nukem. Had a good time playing the PS2 version of it.
Not really. You can’t get the monsters to kill each other. Well, I couldn’t.
ROTT was my return to gaming recently, after I came out of COH withdrawal. Tons of fun, but the later levels were so buggy I finally had to give up about 95% of the way through.
Then someone here recommended Borderlands, and I’ve been happy, if quite dull, for about a year now. 
Eyeing Battleborn but pre-release games tend to be frustrating, and then you’ve blown all the new and fun off of it before it’s stable.
Yeah, I remember getting the Shareware version of* Rise of the Triad *back in the 90’s. It was on a CD Rom software disk that had about 20 games on it from Apogee Games. I later went to buy the full version of Rise at the game store and it was marked as $4.99, but it should have been $19.99 as that was the price of the full version. The cashier rang it up as $4.99 and I got a great game for a fraction of the price.
Apropos of nothing much, the trailer for Battleborn has a very Duke-like archetype pause a moment… and blow a pink bubble.
Depends on the monsters, I think. 
Part of it is the color/humor/wackiness (as opposed to “oh, another brown WW2 shooter!”). But really, I think a large part of it is the gameplay - it’s fast (Doomguy runs something like 47 miles per hour) and filled with enemies. Ever since graphics turned 3D (and graphic detail scales along with graphics power) most games limit you to something like 4-5 monsters on the screen at once, whereas sprite-based games can throw hordes at you. This is what Serious Sam brings back to the table - great huge groups of enemies.
