DUSK

this is one of the best boomer shooters I've played. the guns go bow plink boom poomf and shwing. the bhops go hun hun hun footstep footstep footstep. and it spooky boo .

I am prepared to make the bold and irresponsible claim that DUSK is so good that it's actually better than the id software classics it is trying (and succeeding) to imitate. And I love Doom to death.
It checks all the boxes: fast movement speed, lack of fall damage, intertwined and interesting maps (which are designed to be played with no starting weapons), plenty of secrets to find (none of which are timed, I think, unlike the ones in Doom!), and plenty of enemies to shoot with a variety of familiar weapons. On top of that, there are environmental objects that you can use in clever ways, though moving and manipulating them can be janky. And the game also plays with darkness in some levels, which I thought added to the atmosphere.
My only gripe with it is the music: it's good, but the intense battle action music kept playing when I had already killed all the enemies and was just exploring the map. It happened too often and got pretty annoying, so I had to disable it entirely.
I recommend playing on the second highest difficulty, Cero Miedo. The game will try to tell you that it's "not recommended for a first playthrough" -- ignore it, you'll be perfectly fine if you've played a video game before, and might even find it to be on the easy side. I do not recommend playing on the Duskmare difficulty, where you die from just one hit. Playing on Duskmare is tedious, especially if you're not savescumming, and requires you to become intimately familiar with the maps. That might not sound too bad, but you'll be forced to skip some of the sections and boss fights, and that's just not fun. Whichever difficulty you choose, absolutely do enable "intruder mode" -- that way, all the secrets you find will be much more rewarding and exciting.
Bonus fact: this game came out on same day/month that the original Doom did!

Great game. Do not let it fool you that it is but a retro shooter.
It has a deep atmosphere, amazing level design and combat that will keep you playing for hours.
100% recommend.

I'm late to the boomer shooter revolution, but I now see why Dusk is considered foundational in the genre. The short answer: the level design is brilliant. After playing through all three episodes, if I were to make a ranking of the most memorable FPS levels, Dusk would easily have several entries in the top ten. The experience is varied from claustrophobic corridors to combat arenas to wide open spaces. The environmental storytelling is top notch. As the game progresses, the aesthetics of the environments change significantly and in interesting ways. Just superb.
Secondly, and this is more a matter of taste, but I adore the horror-pastiche-as-theme vibe that Dusk exudes. I caught references to Texas Chainsaw Massacre, The Witch and H.P. Lovecraft. I'm sure there are many more references which went over my head.
However, it's not all sunshine and roses -- er, I mean, bloodstains and meathooks.
The weapons are... fine. Pistols, shotgun, super shotgun, assault rifle. You've seen all these before. There are no secondary fire modes beyond 'look down scope'. The most interesting weapons here are the shoot-through-walls crossbow and the sword which can charge and parry. The most fun weapon is the mortar launcher, whose rounds can be detonated mid-air with a secondary click.
The boss fights are merely perfunctory. You'll not find more here than a fat health bar and a mess of bullets to dodge. See 'Turbo Overkill' for a more recent entry which managed to do more to make boss fights interesting within the genre.
The final two levels of the game have a difficulty spike which seems a bit rough. A late difficulty spike is certainly not unheard of for shooters, and you can adjust the difficulty setting at any time, so not a big deal, but it did put a slight blemish on an otherwise flawless level progression for me.
Still, despite my criticisms, I absolutely recommend a playthrough. Dusk is worth it.

If the Discord server I am on didn't vote for Dusk as our monthly game, then I most likely would not have heard about it.
This game gave me old-school DOOM vibes, just with a scarier world and a way more horrifying enemy design. The weapons at our arsenal feel, sound, look, and play amazingly. Even with its old and pixelated graphics, Dusk manages to maintain an incredibly eerie mood throughout. The game's phenomenal soundtrack and sparse use of lighting contribute to an eerie atmosphere.
Dusk also has an HD-remastered version. Once you start the game on Steam, you get to pick between the original and HD versions. I have to admit that the original version was more pleasing to my eyes. I think it looks way better than the HD version of the game.
While playing the game, make sure to keep your eyes out for secrets and hidden places. There are some hilarious Easter eggs in the game. Without giving anything away, all I'm saying is baby faces!

This was (if I'm remembering right) one of the first of the wave of retro boomer shooters. That might make you think it's a little more generic, a little less creative, than the games that came later.
You'd be wrong.
The level design here is immensely creative and fun - almost like a tour of the best custom Doom/Quake levels. They also manage to avoid a lot of the pitfalls of classic level design (like the over-reliance on mazes) while still feeling believably retro. I really want to say more, but I don't want to spoil some of the cooler sections, so I'll just say: It's great!
The art & environmental design is phenomenal, too. There are some scenic moments in this game that made me gasp out loud (and then hammer the screenshot button). Stuff that I would expect in a Kitty Horrorshow game, not a rambunctious boomer shooter. I never knew quite what to expect when rounding the next corner.
And, naturally, the gameplay is basically fun-in-a-can. It absolutely feels like one of the classic 90s shooters, in a good way - it even has bunny hopping. It's admittedly nothing you haven't seen before, but hey - if it ain't broke, don't fix it. Dusk is already doing plenty of unique stuff elsewhere, so I think keeping the gameplay classic (but very polished) was a good move.
If you like boomer shooters at all, this is a must play.

The game where even the chickens want you dead
This game grabs you, throws you into a blender of blood, bullets, and retro-pixel terror, and somehow makes it fun. Imagine Doom and Quake had a baby who’s really into horror movies and heavy metal—and then fed it pure caffeine.
Levels are pure chaos, enemies appear from every shadow, and the only way out is through a hail of shotgun shells and adrenaline. Also, the soundtrack? Absolute fire.