Hardest game/difficulty in a game you've ever beaten?

Games are hard. Especially S.T.A.L.K.E.R : Clear Sky on Master difficulty, which I'm going to play to begin my 2 month "no pain, no gain" gaming until the holidays.  
Any brutally hard games you've finished on the hardest difficulty? 
Did you do it for the challenge, or do you just like inflicting pain on yourself?

Bangai-O Spirits.
 
Although honestly it's not too hard. It just starts off that way.

I guess the most recent was I finished Call of Duty 2 on the highest difficulty a few years back. I don't know why I was doing it then, I still don't know why I did it.  
 
Fuck AI grenade spam and infinitely respawning enemies.

I never beaten any of my Castlevania games so I can't say much.Lately I am trying Halo:Reach on Legendary, and holy hell.One of the hardiest FPS's I have played.The A.I. is ruthless and the "enemy scaling".I don't think I will beat this one neither.

@Agent47:
......HITMANAGENT? 
 
Is it noticably harder than halo 3 legendary?

gears 2 on insane

Call of Duty 4
Modern Warfare 2
Uncharted 2
Halo Reach
Gears 2
Splinter Cell Conviction
F.E.A.R. 2
Resident Evil 5

This thread made me realize how few times I've played through games on hardest difficulty... I usually play on normal not to wreck the experience with getting frustrated and then I kinda just forget about hard.  
 
My most fresh memory is definately Halo 3 on Legendary. Even though it was a blast talking smack with my friends while playing etc. when we got to the level Cortana I was seriously doubting my skills and 4 hours later still on the same map I was considering playing Dora the explorer instead. That map is mad horrible yo.  
 
Gears of War 1 was also pretty intense. I remember killing RAAM at the same time as he killed us after an hour of wiping or so. He was falling to the floor as the movement was slowing down and the screen turned red. I didn't even think that was possible. 
 
I've also beaten Splinter Cell Conviction on "Realistic" but it isn't really hard... There were maybe 4 scenes where I got the "WTF? This can't be done" feeling I usually get from hard games. Fucking hate the Iraq(?) level. 

Anyway, I need to finish something on hard... Anyone got any recommendations?

Demons Soul... no just kidding that games not hard.
 
I would probably say Devil Survivor, Naoya first play through.

I normally play games on easy, sometimes on normal. I totally get how people could enjoy the skill/challenge of beating a game. But I really dig games for the immersion and interactive narratives I can't find in any other medium. Brutally hard hard games just get in the way for me. Some people skip cut scenes; some play on easy. It all depends on what you want from your game.

I beat MGS4 on big boss extreme in under 4 hours. I know I have bigger accomplishments than that but I have bad memory.

Whats with all these modern games? You guys are pussies.
The Lion King for SNES was a motherfucker (some of you know what I'm talkin about.)

Demon's Souls 
Platinum Arkham Asylum (don't know the general opinion on how hard it is to get all the achievements/trophies) 
Uncharted 2

Call of Duty 4 was definitely the most agonizing hardest-difficulty run I've ever done in my life with video games. Call of Duty 2 had trouble spots, but there's one portion of Modern Warfare that nigh-impossible on Veteran. Just shitty AI and arbitrary checkpointing and infinite respawns atop a level predicated on a time limit. Perhaps some of the worst design I've ever seen in a video game, in terms of difficulty balance. 

Soloed hell mode  in Diablo 2. No fancy gear, no cheating.
CoD4/MW2 veteran mode... I had more fun than frustration actually.
That's about it :|

" Soloed hell mode  in Diablo 2. No fancy gear, no cheating. CoD4/MW2 veteran mode... I had more fun than frustration actually. That's about it :| "

" Whats with all these modern games? You guys are pussies. The Lion King for SNES was a motherfucker (some of you know what I'm talkin about.) "

I guess Mass Effect and Mass Effect 2 on Insanity. My ME run was at level 60 with infinite Immunity/Marksman so it was a trivial process, but I did play through ME2 Insanity from both level 1 (Vanguard) and level 30 (Infiltrator).  I plan to start ME3 at Insanity from the get-go. Should be easy if the systems don't change too much.

My first time through Uncharted 2 was on Hard, I would have finished Crushing but my save corrupted halfway through so I just gave it away. I fucking hate unlockable difficulty levels.

Now that I've got its patterns and such pretty well memorised its not that hard, but my first (inordinately large number here) or so attempts at beating Battle Toads were pretty intense. Then again, I also played that game when I was pretty damn young.

Fucking Ghosts and Goblins. At a certain point it wasn't even fun anymore, and by the time I beat it I hated myself.

" Whats with all these modern games? You guys are pussies. The Lion King for SNES was a motherfucker (some of you know what I'm talkin about.) "

Demon's Souls is hard the first playthrough but really not all that.  
 
Fuck you, Maneater.

Call Of Duty 4 on Veteran. or better yet High Mile Club mission. 
Gears Of War on Hard. By My Self.

" @BionicMonster said:

" Whats with all these modern games? You guys are pussies. The Lion King for SNES was a motherfucker (some of you know what I'm talkin about.) "

Damn straight  "

A lot of the games I have seen listed so far aren't what I think of when talking about games that are fuck off super hard.  If I had to list what were the hardest games for me, then it would look something like this.
 
Forbidden Siren - Its a game for crazy people and if anyone ever says they beat that game without a guide then they are a goddamn liar. A lot of the difficulty comes from how abstract and incomprehensible the thing is at times, but it is also nonstop tension and terror, which is fucking awesome.
Shin Megami Tensei: Nocturne - No explanation needed.
Resident Evil 4 - Professional mode doesn't fuck around. 
Super Ghouls and Ghost - Again, no explanation needed.
Final Fantasy Tactics - When I think back on beating this game I can only remember two things about it. 1. It had a great story. 2. Many, many soul crushing defeats that robbed me of hours of my life.
 
Other games that I got close to beating but just couldn't do are Ninja Gaiden on NES, Doom 2 Nightmare mode, and Aladdin on Sega Genesis. Oh, and BionicMonster is totally right, The Lion King for SNES was an evil motherfucker of a game. I never got past the third level.

"A lot of the games I have seen listed so far aren't what I think of when talking about games that are fuck off super hard."

"Shin Megami Tensei: Nocturne - No explanation needed.  
 Super Ghouls and Ghost - Again"

I've beaten a lot of games in my day, but I can't think of any that were super hard. Maybe Jak 2?

I thought Comix Zone on the genesis was pretty damn tough.  I remember renting it quite a bit,
 
And the Devil May Cry games on Dante Must Die, always a pleasure.  Heaven and Hell difficulty was cool, too (you die in one hit, the enemies are on hard difficulty)

"I've beaten a lot of games in my day, but I can't think of any that were super hard. Maybe Jak 2? "

surviving 1mil in geometry wars was kinda tough but very enjoyable.  ME and ME2 were pretty easy on insanity but both were a lot of fun.  actually Mass Effect was real easy once i had my sniper rifles setup.  Dead Space was easy and just tedious.  did it with just the plasma gun for a little fun.
 
back in the day Shadow of the Beast and Blood Money were pretty tough.  I didn't finish either.  Rushin Attack was tough on the NES.  felt pretty good finishing that one.
 
my issue is that it's hard to find a game that's both difficult and fun to play at the same time.  there just aren't many.
 
take splosion man for instance.  hard mode on that would be pretty difficult, but not in a good way.  collision detection and framerate are way too glitchy to support a no-checkpoint playthrough with single-shot kills.  It's not a case of the game being hard, just poorly designed and executed.  hard mode boils down to fighting against poor coding.

" Lost Planet on hardest would be the one that I'm most proud of. Each level on the hardest difficulty took about a solid day of beating my head against a wall to get through. That plus getting all the target markers while your T-Eng is constantly draining is the worst. "

F.E.A.R on Extreme. I loved that game.

I'm kind of a pansy when it comes to difficulty. The hardest thing I can think of is Resident Evil 4 on Professional, and even then, it's not that hard.

" @ZombieHunter said:

" @BionicMonster said:

" Whats with all these modern games? You guys are pussies. The Lion King for SNES was a motherfucker (some of you know what I'm talkin about.) "

Damn straight  "

Demon's Souls walks up to you, knocks you over the head with a mace, bends you over a table, and (BLEEP BLEEEEEP BLEEP BLIPPITY BLIPPPPPP BLEEEP) 

The Super Star Wars games. Those games are a bitch. 

Half-Life 2 on the hardest setting.

" The Super Star Wars games. Those games are a bitch.  "

"

@Agent47:
......HITMANAGENT? 
 
Is it noticably harder than halo 3 legendary?

"

Killzone 2 on legendary almost killed me.

generally vvvvvv wasnt that hard, but this part was a true motherfucker
 http://www.youtube.com/watch?v=4CtiY5D6HCs
looking forward to super meat boy, and also i beat stuff like mw1 and mw2 on legendary, and i know ill get some flaming for this, but i beat dog days on the hardest difficulty as well, which was a bitch considering how bad that game is at letting you know how badly injured you are

I couldn't say the hardest gaming experience I've had on the highest difficulty, because I never took an interest in playing games on their hardest difficulties until I got my Xbox 360. Beforehand there was no real motivation. I suppose the hardest that I can think of has been Call of Duty 4: Modern Warfare. Of course, if I go through Call of Duty: Classic on Veteran, that would likely be harder. I need Call of Duty 2.... one of my friends has it, and never plays it. Plus, I was getting through Veteran difficulty at a decent enough pace.

I beat these games on the hardest difficulties:
 
God of War 3
Modern Warfare 2
Uncharted 2
Batman Arkham Asylum 
Devil May Cry 4
 
Probably more then that, but those are the ones I remember. I also am in the middle of my Mass Effect 2 insanity run.

Too much stuff to name, honestly.  I always try to go for the hard mode achievements in everything I play.  I think Lost Planet was the one I just couldn't stand (constantly decreasing health is a shitty way to structure a game and I got fed up with it about 5 levels in).  Just look at my achievements if you're interested.

I don't even play that many games on hardest mode, in fact I don't even play games on hard until this generation, since they've gimped so many games' difficulty, so that's easy for me to list:

God Hand on hard
Uncharted 1/2 on crushing.
Bayonetta on non stop climax.
Persona 4 on expert
DMC4 on DMD

The hardest game was god hand, but it was really fun, and I usually hate hard games, that says a lot about it.