Most Difficult Achievement To Obtain.

[MercenaryCanary]

I would have to say Mile High Club, I know everyone else has said it, but holy crap is it difficult.

But you have to admit, your heart was thumping, you were on a fucking adrenaline rush by the end of that level. I know I was.
As for hard achievements, I'm going to go with Your Show Sucks. Dude, for some reason, it won't unlock for me. I played the level on my friends account on Veteran difficulty, shot every T.V. and beat that level for him, and he walks off with two achievements and gets the credit.

 

[Jambolaty]

100% completion on lego star wars the complete saga.
impossible because you would kill yourself from boredom half way through.

 

[Zersy]

Beat the Epilogue on Call of Duty 4 on veteran..... IMPOSSIBLE!

actually this is suppossed to be one of the easiest ones

it's shooting the Sniper from hell in COD5 thats IMPOSSIBLE !!

 

[Don't taze me bro]

I'm currently at 9/10 sentry kills in one life with an engineer in TF2.

Kill 1 person, no one cares
Kill 2 people, someone will tell the rest of the team there's a sentry where you put it
Kill 3 people, their team will coordinate it's demise

Killing 10 in one life is just nonsense, at least if you want to farm achievements the proper way; with no modded levels or goofy rules.

I only just did that one recently. I ended up doing it in Badwater Basin (payload map), playing as Red (defence.) I set my turret up on the roof, to cover the second payload point. I ended up getting around 23 points in one life.

And I agree with you. I have only ever strived to get achievements playing properly. I still don't have the Ubersaw for the medic, or the Backburner for the pyro. I'm ok with that though. I know I've done what I have legit.

 

[Kujikenaikara]

I'd have to go with 'Nothing Special' in Left 4 Dead.

Taking no damage from any special infected becomes a huge problem when you reach stage 4 and the AI director drops a witch in a narrow corridor that you are forced to go down, and then a boomer right beside it so the computer or your partner shoots it.

 

[Exploding8]

I wanna be the guy on Impossible.

^This^

*sigh* good times... or were they.... 0.0

 

[acer840]

The most annoying one and difficult one that I achieved was the Gunslinger in CODWaW. About the 10th try at it, I managed to kill him with the pistol... and no achievement came up. Of course at that time i was pissed and I rage quit. It took me a further 20+ goes to finally get it. Also counter-sniping on Veteran on the same mission was a *****. I still swear to this day that sniper had the first heat seeking bullets in the world.

 

[Shycte]

I'd have to go with 'Nothing Special' in Left 4 Dead.

Taking no damage from any special infected becomes a huge problem when you reach stage 4 and the AI director drops a witch in a narrow corridor that you are forced to go down, and then a boomer right beside it so the computer or your partner shoots it.

That one is a real *****...

 

[Rad_Brad]

Little rocket man.

trying to carry a garden gnome several miles through Half-Life 2 Episode 2 while being chased by a helicopter gunship is HELL!

Aha! Yes, that's bluddy annoying! As well as the 'Save One Bullet Achievement!' Mann, play through the whole of HL2 Episode one (I think) Firing only one bullet! >.<

 

[Altorin]

5 star every song on expert on any guitar hero type game.

 

[Altorin]

100% completion on lego star wars the complete saga.
impossible because you would kill yourself from boredom half way through.

I actually almost did that.

It's not that hard, it's just tedious.. and Tedium isn't hard when it comes to achievements. The ones that are the really annoying ones are based on pure dumb luck, going online when you don't have XBL, or are based on something that takes years of practice to do.

Or the ones in Blue Dragon based on PERFECT execution of minigames that you don't get a chance to get expert at because you only get one chance at them.

 

[Altio]

Master Baiter in Pro Bass Challenge 2008: Get the secret "Wacky Willy the One-Eyed Wonder Weasel" Lure to squirt its secret fish attracting liquid.

But in all seriousness I'd have to say beat Through the Fire and the Flame 100% on Expert in Guitar Hero (2?)

EDIT: Just in case there are morons out there, the wacky willy thing is a stupid name for your... um... meat and two veg.

 

[hem dazon 90]

the gnome oh god the gnome

(goes into fear & insanity induced fetal position

 

[Gado911]

I would have to say the hardest achievements to get with your Xbox 360 is either "Don't get the rings of death" or "Never have to send your Xbox 360 back to get fixed."

I hade my 360 for 5 years and never got any of these problems.

 

[HPoirot]

Ironically I found Mile High Club rather easy once I knew what to do.
If you find a good guide on youtube and follow the strategy it gets alot easier.
However, I still can't beat the COD4 sniper levels on veteran.
I can never get to the helicopter once it lands.

 

[Mewick_Alex]

If you don't use a guide of some sort then killing all the behemoths in fallout 3 is pretty much impossible. One of them makes you follow a set of arbitrary clues (which aren't marked with quest markers) before it even appears, and the last clue doesn't even lead you to the right place!

 

[Lord_Ascendant]

Half Life 2: Episode 2

Get Some Grub: Squish all grubs

BioShock

Finish Game of Hardest Setting

 

[Gaming_Purist]

The "what are you trying to prove?" achievement for L4D looks pretty hard. Gotta complete all those campaigns on expert...

 

[Conveant0]

Ironically I found Mile High Club rather easy once I knew what to do.
If you find a good guide on youtube and follow the strategy it gets alot easier.
However, I still can't beat the COD4 sniper levels on veteran.
I can never get to the helicopter once it lands.

I can help you out, if you end plant your C4 and claymores (Bar 1) around the area with the cars, to the right of the bumper car ride, and the go to the area near where you find the enemy intel, you'll find a change in the wall. Where the wall dips in, stand perfectly still there and place a claymore at your feet. There you have it, the enemies (mostly) will not bother you. When the time to run to pick up your man, you detonate the C4, killing most of the enemies, go to your man and take him to the chopper. Not 100% trust worthy by far, especially at the end, but it does improve your chances.

OT: I'd have to say Steppin' Razor (Only got it recently) from Halo 3, and on COD4 'The Forth Horseman' and 'Milehigh Club'. So glad when I got 100% on it.