Just recently I completed Spelunky the whole way through from the first level to the end. AND I got a fair $180.000 too. And I still had 3hp left. Still not impressed? Wow tough crowd. I managed to do it one time before too! And the first time I did it without the sceptre!
Your still not impressed are you?
Well I beat Sephiroth in kingdom hearts.
And metal gear solid 3 on European extreme.
And I did the little rocket man achievement on hl2 ep2.
And I killed Night Terror in soal calibre 3 (on that challenge mode level)
I am currently fighting the Grox in spore, I have carved a massive chunk out. Taken me days, and a modded weapon but still a big challenge!
Killed the final (I mean really final boss) of Pikmin 2, that guy takes ages!
A bunch of mirrors edge speedruns (cant do the sewer level though)
Resident Evil 4 veteran mode.
Killed the secret final boss of patapon 2 (I think its name is zettenkarman)
God of war 3 titan mode (I know that is not really that hard)
100 level dungeon in paper mario ttyd
Defended all the houses in the valley in hl2 episode 2
Taken the entire island chain in Just Cause.
Edit: I got some more! I once rode on the OUTSIDE of a enemy helicopter in battle feild 2 multiplayer by glitching into it a bit. Really nice view.
You know there is an engine at the start of ravenholm in hl2 in this little wooden bu8ilding? I once taken that all the way through to the centre of nova prospect (the antlion beaches were hell)
Completed black and white 2 battle of the gods dispte how fucking tedious it is.
Completed prototype on the hardest difficulty (cant remember what that is called)
Made the untima kay thingy in kingdom hearts
Slept with your mother
Played fallout 3 with no clothes and only bare fists on very hard difficulty, but then got kinda bored because it was still surprisingly easy.