I've beaten, conquered, and utterly humiliated every video game I've ever played.
Final Fantasies 1 through 7, crystal chronicles (not like that was hard), tactics advance, etc. Though i never got into 8+.
Every Metroid that has been released. Funny story, my first time playing the original Metroid, I finished it faster than the person who was showing it to me ever did.
The Legend of Zelda poses no challenge in any form. Zelda 2 was just plain awful and mind-numbingly simple.
One of my favorites from way back when, Kid Icarus. Loved that game, and after defeating it I found hundreds of codes for it through trial and error.
I once played through Super Mario Bros for the NES for around 50 hours straight, I had a ridiculously high score...wish I still had the picture that showed my final score.
I've tried playing through the city/civilization games, like SimCity, but I never had enough patience to really get into them. Although when playing Tropico last year, I managed to get the biggest island completely covered and up to 2000 people with over $4 million in the treasury and $1.5 million in my swiss bank account.
Oh yeah, in 2005, I was voted the best alliance healer on my server in World of Warcraft in an impromptu forum poll...out of 1000+ votes I got nearly half, while the rest were divided up among 5 or 6 others.
The list goes on...45+ NES games, 50+ SNES games, several dozen N64, Gamecube, Wii and PS1/2 games, and an even bigger list of computer games.
My longest gaming binge was 73 hours straight without sleeping or eating. Looked at the clock and thought to myself "Damn, I got alot done in an hour."
Basically whatever game I touch falls short of providing a lasting challenge. I'd like to get into designing some, but nobody would play them because they would all be too difficult.