Games that kicked your ass.

Play Wipeout HD/HD Fury and get every gold on the first try. Its not really regacy yet but the AI in that game is a b*tch on phantom. 

Play The Witcher 2 on Nightmare and try to go through without getting a single game over screen...and good luck, but you'll need more than that.

Battletoads

Ninja Gaiden 1 and 2 (NES)

Ninja Gaiden (Xbox)

Ninja Gaiden 2 (360)

DMC 1 and 3

Halo 2 (Legendary)

F-Zero GX

MGS2 (Euro Extreme)

Demon's Souls and Dark Souls

Viewtiful Joe leaps to mind.  On Ultra V rated, you more or less can't get hit, especially later in the game... I've made it to the final form of the final boss, and damn, he kicked my ass becaused I got careless.  That game definitely puts hair on any gamer's chest.  It's a true test of gaming ability, without being cheap.

Several:  -Mega Man 7 and X's final bosses were the hardest ones I've ever faced, Mega Man 1 was the most difficult for me overall though as it was the first one I ever played.  

-F-Zero GX's story mode was extremely difficult but I have managed to beat all of the missions on hard and one on very hard.  

-Super Star Wars kicked my ass for a while but I beat it recently.  

-Devil May Cry 3 had some very difficult boss battles, not the hardest though.  

-Zelda II was all-around hard, especially the final temple.  

-Beating Pokemon Stadium 2 on R2 with rentals is definitely one of my biggest gaming challenges, especially the Elite Four.

-I was pretty bad at RE4 and I died quite a bit in that game.

-Demon's Souls is the most challenging RPG I've played through, but if I were to play it again it would be a lot easier.

Catherine

Devil Survivor 1

Persona 3 Portable on Maniac Mode.

I never could beat the 80's Mario Bros. series.

Of the many, Super Mario Bros. 2 comes to mind.. the japanese one. Jesus. That game is ridiculous

After many hours of tears, blood and sweat, trying to get all the way to world 8 and beating it, I was so happy, I jumped for joy, I thought I had beaten the game...

But then, I learn that the game isn't over.. And that there is actually worlds A-E after you beat world 8, and each is harder than the last. I threw down the controller in rage and walked out of my house and walked for many hours thinking about my life and how much I that game made me hate it.

F-Zero GX

Super Mario Bros 2: The Lost Levels

Shin Megami Tensei: Nocturne

Company of Heroes

Getting all 120 stars in Mario 64 - mostly because of the wonky camera.

Never beat Ninja Gaiden for the NES.  But I was a kid, perhaps now...nah, I'm spoiled by a decade of easy-mode.

Teenage Mutant Ninja Turtles - NES

Super Empire Strikes Back - SNES

Speed Kings on the PS2 i found to be rather hard when i was testing it last night.

Think 'Burnout on bikes'. But you gain boost by doing risky tricks, glancing off of traffic (but not hitting the fronts or backs), and sliding under trailers that you have 0.5 seconds to react to.

Perhaps with some dedication it will become easier, but for casual-playing in between other games it's a butt-kicker.

Final Fantasy VII, Parasite Eve, mostly any Squaresoft because their games are sooo damn hard.

Parasite EveGSJones1994

Final Fantasy VII, Parasite Eve, mostly any Squaresoft because their games are sooo damn hard.

GSJones1994

Final Fantasy VII is one of the easiest RPGs ever made. I actually don't think I've actually played an easier RPG than Final Fantasy VII. I'm not trying to be a d!ck, but you must be doing something wrong if you think FFVII is even remotely hard.

But to answer the question, even tho it's cool to act like Demon Souls is not difficult, that game kicked my ass hard. So did Ninja Gaiden. I didn't manage to beat either.

A game I did beat but I found hard was Star Ocean: The Second Story. The final boss was a nightmare.

Final Fantasy VII, >GSJones1994

[QUOTE="GSJones1994"]

Final Fantasy VII, >ImJESUS-PROam

FFVIII is not hard either.

[QUOTE="ImJESUS-PROam"][QUOTE="GSJones1994"]

Final Fantasy VII, >GreySeal9

FFVIII is not hard either.

[QUOTE="GreySeal9"]

[QUOTE="ImJESUS-PROam"] You sure you forgot to add another I to VII when you said this?

ImJESUS-PROam

FFVIII is not hard either.

Tedious/=/hard.

Even if you just do normal junctioning, FFVIII is not a challenging RPG. 

[QUOTE="ImJESUS-PROam"][QUOTE="GreySeal9"]

FFVIII is not hard either.

GreySeal9

Tedious/=/hard.

Even if you just do normal junctioning, FFVIII is not a challenging RPG. 

[QUOTE="GSJones1994"]

Final Fantasy VII, Parasite Eve, mostly any Squaresoft because their games are sooo damn hard.

GreySeal9

Final Fantasy VII is one of the easiest RPGs ever made. I actually don't think I've actually played an easier RPG than Final Fantasy VII. I'm not trying to be a d!ck, but you must be doing something wrong if you think FFVII is even remotely hard.

But to answer the question, even tho it's cool to act like Demon Souls is not difficult, that game kicked my ass hard. So did Ninja Gaiden. I didn't manage to beat either.

A game I did beat but I found hard was Star Ocean: The Second Story. The final boss was a nightmare.

[QUOTE="GSJones1994"]

Final Fantasy VII, Parasite Eve, mostly any Squaresoft because their games are sooo damn hard.

GreySeal9

A game I did beat but I found hard was Star Ocean: The Second Story. The final boss was a nightmare.