Cybernoid 1 and 2 are very hard, so is silver surfers and dragon's lair but the game that breaks my will the most is street fighter 2010. An ungodly game with difficult controls, enemies, a time limit and no passwords or continue points to save from so you have to beat it in one shot. I can beat long hard games in one shot like ghosts n goblins but this one just makes me not want to play games anymore despite unlimited continues. What games are your hardest and for what reason.

The hardest Game I've ever played would be Grand Theft Auto 4, but it would be the first  time I played it ever. What made the game hard for me was the fact the missions were hard for me to actually start them and follow the map. Now hack game wise the hardest game for me was Pokemon Darkcry because the map made no sense it was hard to follow and  the hacks creator messed up the Pokemon types with the Pokemon the type is suppose to go with and also what made it hard was the fact that if you talked to certain trainers the game would freeze and make you start over.

Kaizo Mario 3 o god the pain level 5 is s*** insane.

ghost n goblins lol 2 broken snes controlers

ghosts n goblins make me hurt my fist lol, still beat it though but I wa smiserable doing it

I found Ninja Gaiden Sigma 2 quite punishing, as well as Devil May Cry 3 (Not the special edition, the one with the original difficulty settings)

Same here , I broke one controller on ghost'ngoblins and another one for mega man 2 lol

funny enough i'm on the last level of street fighter 2010 now haha, and no it is anything but easy

Famicom or N.E.S. Transformers? (No, that's just too brutal to mention.)

Ninja Gaiden.? (Any of them accept the third one for the X-Box...Someone probably already covered those games.)

Toxic Crusader games? (Any console.... again too broken.)

Ghost's N Goblins? (Too fun and too common again.)

Ninja Turtles 1 for N.E.S.? (Too common and the save state feature practically breaks the difficulty.)
......................
I think I'll Go with "Nightshade" for the N.E.S.
Only a few people in the world have completed that game. It is not a broken game. But it was super ambitious. Allot of fun.
I should be getting to finishing the thing up in this site to write a review and give up all sorts of hints and tricks. (Most are already covered in the photos uploaded for that game.)

Another that no one seems to be able to play well is "Pirates" for the N.E.S.
It is not very hard but most seem to be lost on it. Since I have already completed the one for the N.E.S.? I'll have to withdraw the N.E.S. version for difficulty and Bump up the 16-Bit "Genisis" version as Hard for most. No one seems to have completed it in here that I know of.

I would like to mention Wolverine for the N.E.S.
I think I am the only one who has finished it so far. That game is hard and painful on the ears.
But
It can be completed. (Major Left Turns with the Boss Strategy. ... All of the Boss Characters.)

I'll have to say something about Double Dragon 3 for the N.E.S.
It is the hardest beat-em-up I have ever played. (Yes, it can be completed without the save state feature of the internet copies, but still it has to be mentioned at least once.)

Those are my entries for Hardest games that come to mind.
For some reason I can not think of many in the modern generation right now. Age might have something to do with it. (Alzheimer's setting in already?) (.Joke.)
Good Luck.
Peace.

YES I just did it I beat street fighter 2010, posted screenshots on the page too (theres 2 street fighter 2010 both the same go to the one with my screenshots on it) holy s***e was that hard and annoying.

I would say any early game made by Capcom and Konami with the exception of the Mega Man series. Some of these games they made in those days are still ridiculous to play today. I really got smoked out by Gunsmoke and Section Z recently.

 Azul Fria: hmm never heard of those 2, I find the 8 and 16 games are the only ones that manage to kick my ass clean off. Castlevania III frustrated me a lot too

The hardest game I ever played was link and the ocarina of time it is not really don't know what to do

The hardest game I've ever played is Super Mario Galaxy. I quit after 8 stars because I couldn't get past the first Bowser course boss battle even if I used a walkthrough.

Y'all are probably gonna laugh at me but for me it's Dark Souls. :/ I'm just terrible at it for some reason. Like I'll do just fine for a really long time and then I'll hit some area that I just can't get through and I get seriously frustrated. So yeah, that one for right now.

spiritdragon : well that game wasn't hard for me but I have heard many have got frustrated with that and demon's souls, the only problem I had with it was the bad combat controls, but if you can muscle through that you would be ok. I don't think any 3D game has ever really challenged me which is a shame

The hardest game I have played would need to be part of a whole genre for me and that genre would be almost all fighting games. It relay started with Street Fight 2, but I end up lumping them all together as I'm just horrible at everyone of them. Don't get me wrong, I still love fighting games for the charm and creativity, but I have a difficult time remembering combos and my reaction time is typically too slow. 

I played a few hard games, but they are the hardest games, what I played:

Demon's Soul: It's a  very hard game, becuase some enemies can defeat you with only a few hits(In Level 3-1 the first enemy stun me then it kills me with ONE hit!), and if you die, ALL enemies will respawn, and you will lost your ALL souls, unless you go back to the place where you died without dying. However it's a great game, and you'll think twice where you'll go.(Yes, the levels aren't linear, and you won't get any clues where to go)
Need For Spped Most Wanted: Well, it's an easy game, but when the cops are chasing you, it's so hard to shake off the cops,if you try it, you'll know what I mean.
Any Call of Duty game on Veteran Difficulty: The Call of Duty games aren't so hard, but when you play it on Veteran difficulty,you'll suffer a lot. Two or three shots, and you are dead.
Ponon Deluxe: It's just a small Tetris game for Android, where you can choose between two game modes, Classic and Quest(or something like that) The Classic mode is just Tetris without any difficulty. But the Quest mode is REALLY hard. There is a green line on the screen, and you have to clear away all Tetris blocks above this line within the Time limit. It sounds easy, but you'll often run out of time.
Super Mario Bros The Lost Levels: This game is similar to Super Mario Bros, but it's harder. I had troubles with Super Mario Bros too, but this game for me was a so hard game.

These games the hardest games I ever played, but I think it's relative. Becuase it's hard to me to shake off the cops in Need for Speed Most Wanted, but I think there are some poeple, who thinks it's just a piece of cake. And i know they are some harder games, but I didn't played with every hard game, and I just write down games what I played.