Just beat MP3 on the hardest difficulty, it took me so long because after my first 2 attempts failed(when your on phaaze and you get the slowly filling phazon bar. it just took me forever the destroy that infant and then dark samus AAARRGHH) i got myself MKWii and SSBB. I just picked it up again after 1,5 month and  and you beat it on the first go .

but i hope that buying MKWii and SSBB is a good enough excuus for letting MP3 sitting there unfinished.

PLEASE FORGIVE ME.

Ditto for TMNT. There are three types of people who played those two games:

1. Those who never played them

2. Those who played them and never beat them

3. Those who lied about beating them

That's it. I refuse to accept that any human being has beaten those games without cheating.

PS. Got to the last level of Battletoads once and got to the screen before Shredder in TMNT twice... Fuck those games. Fuck them in their stupid asses.

Thank the Lord that we don't have to suffer through the Kid Icarus/Battletoads/Ikari Warriors/TMNT/etc. any more. Kids just don't understand the kind of masochistic attitude it took to beat those games.

I just beat Half Life 2 for the 2nd time.

And finished HL2 Episode 1 and Episode 2.

I also just finished Portal! Maaan, what a game!

I just beat Blood Omen 2, played it using Gametap and a mapped PS2 controller. The storyline and characters were fun once you got past the "Vampires R teh awesome and misunderstood!!1!1" vibe. the thing that pissed me off were the controls, utterly horrible. No strafe option, which by itself wouldn't be that big of an issue, but the pathetically loose turning radius made it absolutely unforgivable.

I had to have died about twice as often from randomly running into water because it was impossible to turn properly as i did from actually getting killed by enemies, which was usually tied into the second problem; crappy uncancelable button lag. I press the attack button 3 times, Kain attacks once, the enemy winds up for an attack that has to be dodged, I press the buttons to dodge, Kain attacks a second time, the enemy finishes charging the attack that should have already been dodged, I growl in frustration and press dodge again repeatedly, Kain starts to attack the 3rd time and gets the shit knocked out of him while I shout expletives.

It was nice to go through once, but I'm not even considering playing through it again. It was incredibly linear, and the enemies and upgrades were all very cookie cutter. The controls were actually the main source of challenge for the game, not any actual inherent difficulty of the game, and that caused no end of frustration.

One good point to the game were the minor puzzles that required the dark gifts to solve. After playing Zelda for close to 20 years though, most of the puzzles were barely even consciously registered. However what I did notice was that the visual cues that let you know you needed to use a power were much less apparent. Even though the puzzles all solved very easily, I still felt that I was figuring it out on my own and not having my hand held the whole way through.

The thing I enjoyed most were the boss battles, which actually required a decent amount of thought, and a teensy amount of skill on top of that. It was kinda refreshing after hours of threshing through the small fries to have to use your surroundings to attack in the boss battles, rather than just brawling with them directly.
The Final Boss was actually a bit of a letdown though. I died a couple of times trying to figure out the first phase of attack, but once I got past that, I had him down in 2 tries, which is actually a fair bit less than almost all of the other boss battles.

I just beat Tenchu Z. That was a pain in the ass to go through 50 levels of the same shit over and over again.

I just looked up one site's list of the top 10 hardest NES games, and I think I've legitimately (no Game Genie) beaten half of them. Most of them it was only once or possibly twice, but I have done it.

From their list:

10.) Top Gun - Played it a little, but always sucked at it.

9.) Bart vs. the Space Mutants - Awful game, but I beat it. This was a staple rental for my brother and I from the local gas station. (Small towns didn't have video stores 20 years ago.) I think I actually finished this one a couple times, not that it wasn't hard, we just played it a whole lot.

8.) TMNT - I have beaten this. It was one of those "play a while, then leave the NES on overnight while you were at school the next day" situations over the course of 3-4 days, but I did beat it. The ending robbed me of the last few shreds of my youthful innocence.

7.) Yo Noid! - Never played it.

6.) Karate Kid - Ditto.

5.) Double Dragon 3 - This one I beat one time, and one time only. Such a ridiculously hard game, and beating it took a lot of luck. This game I actually owned, and it still probably took me 2 years to get the perfect run of it to beat it.

4.) Mega Man - Beat this one. I recall it being tough, but nowhere near as tough as the other games I played on the list.

3.) Ghosts and Goblins - Beat every last infuriatingly difficult inch of this game a bunch of times, and then I think I beat it the second time through once or twice. This one was pretty much memorization of enemy patterns.

2.) Battletoads - This is another that I beat one time and one time only. Even doing the crow juggle trick for lives on the board where you descend the shaft on the ropes only prolonged the inevitable failure you were doomed to in this game. Beating this is probably my most memorable gaming accomplishment, and I doubt I could ever do it again. It took years of failure to finally get that convergence of planets that gave me the perfect run through it.

1.) Silver Surfer - Never played it. Glad I didn't, since I would have taken the difficulty of it as a personal challenge.

Other notables I can think of:

The Ninja Gaiden NES games (Beat all 3, although I think I beat the third one only one time. Another proud accomplishment.)

Cobra Triangle (Weird boating game. Rented it all the time. Beat it once. Crazy hard.)

Castlevania (I think I finished the original once ever)

Faxanadu (that reference will please one person here. Took me forever to figure out how to use the mattock since I didn't have the manual for the game. Down + B? That would have been nice to know.)

Ikari Warriors (I hate that game. I don't know if I ever got past the second level, and I played it a LOT)

Guardian Legend (I don't think anyone has yet to figure out how to actually beat that game, and the 5000 character passwords with all kinds of fucked up digits in them didn't help.)

There's others, like Kid Icarus, that are wroth mentioning, but it pretty much shows that the NES was far and away the most punishing game system ever created, and had the largest hand in forging the bitter, jaded asshole gamers of today.

Ikari Warriors I don't need those nightmares again.

I just beat warhawk.

Kid Icarus can be challenging, but it's not even on the same level as TMNT or Battletoads when it comes to difficulty.

I actually beat TMNT for the first time last year, and even made a thread about it here. I haven't played Battletoads since me and my buddy rented it and got our asses kicked by it around 91. It's hard as hell, but I still think Ghosts n Goblins is about as hard as it comes for non-shmup/Pac-Man/Tetris-kind of games.

I just beat Phoenix Wright Ace Attorney: Justice for All about a week and half ago, then replayed and beat Trace Memory (yeah the whopping 4.5 hours of it).

I've been in a point and click adventure type mood lately, I suppose.