Too many to mention... But in recent memory, I think the biggest mention is being able to take down George Romero in Black Ops a few times by round 7 in zombies. The patience required to defeat the mofo is practically unparallelled to any boss I can think of the current generation of gaming. Brings to mind Mike Tyson from Punch Out and Jason from Friday the 13th from the days of NES.

My gamer score is 26101. Like Sloth, I pretty much don't really give a damn about racking up achievements nowadays. I only get achievements that I think would be fun to get.

No problem, you can do it by abusing some glitches.
If you look up something like "Mario 64 16 star run" on youtube, you'll definetly find something.
It's even possible to do it with 0 stars, I think this has been done only on an emulator.

I only have a few this generation as I usually just beat the games once or twice in the past and call it a day, and I only play easy games, but these were pretty hard for me:

- Beat Vanquish on god hard
- Beat God Hand on hard
- Beat Rodin in Bayonetta and non stop climax (not really hard, getting a good rank was probably the hard part which I didn't bother).

The only games I've finished recently are Portal and Catherine.

I am not really sure what to put. I have not really tracked most of my accomplishments. Hmmm... On Kingdom Hearts... Whatever the PSP one is called. I exploited the Experience Walker skill to get all my characters up to the max level.

Back in the day. I used to be able to get Super Sonic in the Emerald Zone of Sonic 2

I got all the trophies on Dynasty Warriors Gundam 3... That is an accomplishment

Back in the N64 days. I played Perfect Dark. I used to kill time by setting up Meat Sims, 8 of them and doing an hour long death match between me them and the Golden Guns. I think my record for that was..... 800 kills in one session?

On Starfox 64 I got all the medals on Expert Mode.

That is all I can think of right now.

Able to solo multiple rounds after whole team died in Killing Floor.

Beat S.T.A.L.K.E.R.: Shadow of Chernobyl within 24 in-game hours, without hacking. Just a lot of caffeinated drinks.
In another playthrough, I found a free VSS Vintorez (silenced semi-automatic Sniper Rifle that uses 9x39mm rounds, the same as a powerful assault rifle).

Built a forest inside a mountain inside Minecraft without using Bonemeal.

Being able to still pickup Captain Falcon in Super Smash Bros. for the N64 and kick some serious ass.

Oh yeah I actually completely beat Bomberman 64... what a horrid horrid trial....

-Got 100% on Super Meat Boy, which took ages
-Black Pearl Starflower on Hexic HD
-Did Hard Core mode on Dead Space 2 (you only get 3 saves on the hardest difficulty)
-Mass Effect and Mass Effect 2 on Insanity mode
-Just completed all the achievements on Dark Souls
-Got A rankings on all of the classic Resident Evil games (Playstation era)

I like going for the achievements on Xbox 360. For me, it just adds an extra dimension to gaming. I'm not really bothered about gamerscore that much, but I find it quite fun trying to tick off all of the individual challenges. It's a good way to unwind

I wouldn't even think about trying that. It sounds like it would be the most infuriating thing ever having only 3 saves on such a hard difficulty.

Beat a player controlled lvl. "4" X-Factor Wesker in Ultimate MvC3.

i started playing last season and ranked number 2 in silver.
aiming for top 8 in platinum next season, and if i get good enough, top 8 in diamond in the following season, but i doubt i'll get into diamond.

Beat demon souls twice....
beat zelda master quest...
one of the best holy paladins on my server for pvp...
got almost all the eggs, and got to the key in Banjo kazooie
kick ass at geometry wars...
got the send a gardengnome into space achievement in halflife orange box.... without knowing it was an achievment till i was almost there
basically i found a garden gnome then me and my friend thought it would be funny to carry it around... then i carried it around for multiple levels... then noticed it was an achievement

shit... cant think of any others...