Recommend me a singleplayer shooter

Prerequisites:
- Must be challenging, but not in a cheap way
- No cover mechanics or auto health regen
- PC only

Games I liked:
Doom 1/2, Blood, Duke Nukem 3D (espeically the WGR2: Siegebreaker mod), Half Life 1/2, Quake 1/2 (not 4), most of other classics. Really looking for something good/decent that I missed.

Boarderlands is my go to shooter suggestion, but it's not incredibly difficult. If you get a buddy to afk, though, you'll get stronger opponents.

I can think of two that have impressed me in the past year.

First one Metro 2033
http://store.steampowered.com/app/43110/
Though it does break the health regenerating rule, the game can be some what difficult at times. I also like the way its difficulties are handled. http://metro2033.wikia.com/wiki/Difficulties
The "harder" the difficulty, the less damage it takes to kill both the enemies and for them to kill you. Even though the Ranger difficulties say DLC on the page, they come free with the Steam version of the game.

The second game is Serious Sam 3
http://store.steampowered.com/app/41070 ... uggest__13
I'm pretty sure you might be familiar with the series, but this one is different from the others. Unlike the previous game, this one has reloading, ADS, and Sprinting, but still has health bars that don't regenerate and still a billion enemies on the screen at once. On the easier difficulties, the game can be a cake walk, but on the harder difficulties, it is a challenge.

EDIT:
Also another game I haven't played myself, but have heard good things about is Cry of Fear. http://www.moddb.com/mods/cry-of-fear
It's a HL1 mod but as the page says, it doesn't use any of it's features and feels like its own game.

Any of the Serious Sams. Never played any of the full games, but the demos alone were somewhat challenging, and I've heard good things about the series.

Try playing doom 2 with brutal doom on : http://www.moddb.com/mods/brutal-doom/downloads
The game gets alt fires, reload animations and fatalities.

Edit: Add me on steam if you want me to give you skull-tag and a whole bunch of doom engine games and mods, including a total conversion of doom 2 to Batman

Didn't like it. Too easy and too monotonous.

I liked the game, but more for it being russian than for the gameplay.

Played the first/second encounter and SS 2, I'll try this one out.

From what I understood it's more of a horror than a shooter. I'm looking for a game that I can w+m1 in.

Didn't like it. Doesn't really make up for a game. I played some doom 2 mods, after a while they just became boring.
I also have skulltag and I play deathmatch sometimes.

Also, if you care about story, the Bioshock games are incredible. If you don't, the second game still allows you to run around with a drill, industrial rivet gun, a gatling gun, a double barrel shotgun, a Captain Ahab grade speargun, and a grenade launcher firing homebrew explosives. Not OVERLY difficult, but some planning is required on hard.

Tom Clancy's Rainbow Six 3: Raven Shield gets my vote. I found it challenging, plus has a good set of expansion sets for additional gameplay.

I enjoy the story, but that's not what I'm looking for atm. Both games were incredibly easy on the hardest difficulty, in both games I ended up running with max everything and almost meleeing everyone to death.

Not really a fan of realistic tactical shooters, was more thinking about some mindless all aim no brain doom-style run'n'gun, but I might try it anyway.

Have you played Far Cry? It's not bad although I found it got a little repetitive towards the end. It's not really mindless run and gun, except for a few cramped indoor sections, but it's not quite as fiddly as something like Raven Shield either.

If you want something really old-school, you could also try 8bit killer. It's a freeware game which is somewhat of a homage to old shooters, complete with Wolfenstein 3D-esq graphics. It's not very long but since you're a fan of classic run-and-gun shooters you might find it amusing. And it is free, so no harm in trying it.

You've likely already played Heretic, but if you haven't it's basically "Doom, fantasy edition". You can get it and all its sequels on Steam pretty cheap.

If you don't mind top-down shooters instead of FPS, Shadowgrounds and its sequel offer plenty of straightforward alien-blasting. They are a lot like Alien Swarm, if you've played that (it's free on Steam if you haven't). I found Shadowgrounds to be a bit buggy and not as polished as a AAA title, but it's still pretty fun.

when you do a custom serious sam game it can feel a lot more fun and rewarding of good aim.

like 0 deaths, unlimited ammo (because **** reloading), all weapons by default, enemies at higher health, ect. although you said single player, I couldn't suggest 4manning a custom game more.

Sort of a joke since, beyond Doom and Quake, there aren't many challenging shooter games out there that don't hold your hand the whole time. There's Serious Sam that's pretty much W+M1 with the occasional "oh god I'm dying" bit. Get's real dry real fast though, in my opinion.

Played it a bit at friend's house when it came out. Didn't like it. Didn't try the sequel.

Played it for about 20 minutes, wasn't hard, but really really repetitive.

Played Hexen and Heretic, but haven't touched any of the sequels, never heard anything about them.

No, that's not what I'm looking for.

Well, I got my hopes back when I played WGR2: Siegebreaker. It was released in 2009 (with last update in 2011) while being pretty much the best singleplayer FPS game I've seen so I thought there's probably something good in the past years that I've certainly missed.

Halo 2 Vista

COUNTER STRIKE CONDITION ZERO DELETED SCENES Don't buy it, it sucks ***.

Best bet is to stick to games pre-Call of Duty 1. After that, everyone else wanted to be the next big CoD...then CoD4 happened and yeah.

Timesplitters: The PC port

I'd suggest you try out Medal of Honor Allied Assault, it's actually made by the team that made Call of Duty 1, it even comes with a still very lively multiplayer. Other than that, Return to Castle Wolfenstein and other older shooters, maybe even Unreal 2.

Can seriously recommend Doom 3.

If you really want a brainless shooter with stupidly over-powered AI and absolutely no story that makes sense whatsoever, try this: http://en.wikipedia.org/wiki/Pariah_%28video_game%29

Singularity
Painkiller Recurring Evil
Bulletstorm

If you like Action-RPG, I recommend you 2 classic games:
1) Deus Ex;
2) System Shock 2.

If you do not, then "no" is "no".

What about Rise of the Triad? It's made by the same company and in the same (heavily modified) engine as Wolfenstein 3D. I vaguely remember liking the shareware version when I was younger. I'm not sure how it will hold up these days, but it seems like it would be close to what you're looking for.