Hardest Achievement?

I'm not sure which one is the hardest, but here are some I think are worth mentioning:

Out of all my achievements, the ones I'm the most proud of are probably Golden God and The Golden Gift from Super Meat Boy. As I posted in my earlier reply to a post about The Golden Gift, I still think Golden God is more challenging because it requires much more effort over the course of a long time. I admit I might have been a little addicted to the game when I got it, but the feeling of accomplishment after beating a challenging level after dozens of tries was so intoxicating that I got hell-bent on beating the whole game. SMB still remains one of my favorite games ever. I've done some Iron Man runs as well, so far Maggot Boy has been the most challenging.

Something in Half-Life games awakens the achievement hoarder inside me, and I've got every achievement in all three Half-Life 2 games. And I'll tell you this: after getting Little Rocket Man, I hate Gnome Chompski with great passion. Although carrying him around, looking at his stupid face for couple of hours actually made launching him into space actually feel rewarding.

I have most of my hard earned achievements on the X360, but if we're talking steam only.

Portal: Aperture Science
Earn gold medals on all Portal challenges.

Limbo: No Point in Dying
Complete the game in one sitting with five or less deaths

Caress of Steel in Ys Origin. That's getting through the boss rush on nightmare difficulty with all versions of all characters, 8 in total. I've been able to do it with the two versions of Hugo and that's it. I have all the achievements except that one and the one to earn every other achievement.

Life.

pacifist payday the heist ofc

Offspring Fling - All rainbow flowers (can't remember the legit achiev name)
It's nearly impossible.

The most difficult I can think right now:

• STILL SOMETHING TO PROVE: Survive all campaigns on Expert. (Left 4 Dead 2)
• No Point in Dying: Complete the game in one sitting with five or less deaths (LIMBO)
• Golden God: 100% the game (Super Meat Boy)
• Platinum God!: 100% the game (The Binding of Isaac)
• Speed Run: Complete a full speed run, beating the challenge time. (Braid)

Almost there:
SO MANY LEVELINGS!!: Get to level 100. (Frozen Synapse)

this

generally garry's mod has many weird-hard-funny achievements

YES! I'm the real garry!..... you know what.... FUCK that achivment! garry does barly not even play Gmod anymore >:C

I know every hard achievement so i can say that true form from jamestown easily deserves the price

End Game in Secret Of The Magic Crystals.

"Orange Star", "Leader of Men", "Doer of Deeds" in Realm of the Mad God and "Have my axe" in Killing Floor

all stars in sonic all star racing transformed...i_just_hate_traffic missions on expert

Hardest achievement is the achievement for getting all achievements in all games.

Clearly that achievement in shogun 2 you have to be the best in the world

By the numbers: http://astats.astats.nl/

For me it was Bulletproof Windshield from L.A. Noire. I spent all day shooting at these guys. To make things worse Rockstar Social Club has the audacity to claim I have no achievements in the game, nor have I apparently played it at all.

Shogun 2: Become a Shogun (even in normal diff, having both influences -shogunate and empire- the game gets extremely hard since you're getting attacked by pretty much every other general that is in favour of the shogunate)

The hardest achievement for me has to be any Ironman achievement, X3 has a couple that are just insane. There are plenty of grind achievements, like the random one from BUTTON or the Garry's Mod 1 year idle one but neither are really "hard" to get. They just require lots and lots of idle time.

Yes I am the real garry and 1 year.

Every multiplayer related when game is dead.

I downloaded super meat boy in order to complete the achievements and i played just the forest and I skip playing because i found them hard to achieve

Max Payne 3 - The Shadows Rushed Me
Beat New York Minute Hardcore.

For those of you who don't know, in NYM, you only have 1 minute to beat each level, and you get bonus time for killing people and it's set to hard mode.

In NYM Hardcore, if you die, you get sent back to the start of the game. You have to beat the entire campaign, on hard mode, without dying once.

Max Payne 3 - The Shadows Rushed Me -
Beat New York Minute Hardcore.

For those of you who don't know, in NYM, you only have 1 minute to beat each level, and you get bonus time for killing people and it's set to hard mode.

In NYM Hardcore, if you die, you get sent back to the start of the game. You have to beat the entire campaign, on hard mode, without dying once.

playing 1 year of garry´s mod and sandbox

worst is playing on the same server as garry, take in fact that newman barely plays his game at all these days, the only reasons he play is either to test it or because his friends (who already have the achievement) invite him to a (private) game