Edit: because everyone else is writing such excellent and memorable follow-ups I wanted to expand on the quickie 30-second blurb I originally wrote.
Old memory: Figuring out and memorizing the patterns for stages for 6-2 and 6-3 so I could finally beat Ninja Gaiden, circa 1992.
I first played Ninja Gaiden as a rental in 1989, I asked for it, and got it for Christmas later that same year, along with Contra and two other NES games. When I had originally rented it, I got stuck at stage 2-2 despite unlimited continues. This hurt my young gamer's pride. By comparison: on Christmas Day, I had beaten Contra on my 3rd playthough with the code (within the first half-hour), and before the night was over, I could 1cc it without the code.
THIS WOULD NOT DO.
I played it. Got past 2-2, kept playing, got stuck a few more times, and got pissed at it. Stopped playing it for a few weeks. I played more and got better and got farther through the game. Ocasionally I would get stuck and put it away for wees or months as I hat other games to play (and school and shit).
Got to 5-2 and got stuck again at the "impossible" jump, after many, many, MANY, failures, I eventually found a way to glitch past it. Got to Malth, got stuck at him, until I figured that there is no secret because his attack is too hard to dodge, so you just run up and wail on him and hope that get enough hits in before he kills you. Then get past the next stage without too much difficulty (no holes to get knocked into), then: BAM! Stage 6-2 hit me like a ton of bricks. I couldn't get past it.
No matter what I fucking did: go fast, go slow, different sub-weapons, go carefully, take risks, alternate, nothing worked. Fucking birds, bats, jetpack-ninjas, pumpkinheads, those little green jumpy-things, that discus dude. FUCK ALL OF THEM. So many time I wanted to break the controller. So frustrating. FUCK FUCK FUCK.
The Angry Video Game Nerd review of Ninja Gaiden expresses what I felt perfectly (well... minus his really creepy constant coprophilia, anyway...).
I had to put the game away for purposes of maintaining sanity. I didn't touch it for months.
Months pass. sometime around the spring of 92', I was at the house of one of my mom's friends, playing with her kid who was the same age as me, but who I didn't know. We were playing Nintendo quietly, until the kid's big brother comes home and kick off whatever game were were playing, and puts in Ghosts and Goblins. I objected as I hated the game, since I had rented it some time before and couldn't get past the first couple of screens since it's so goddammed hard.
I was getting bored, until I see him do this thing with Arthur : he got just before to Red Arima and ever so carefully inched forward, I asked him what he was doing, he told me; "watch" and inched forward one more time, and Red Arima got stuck, glitched, and disappeared.
He told me what he did was "suffocation", that there was a "magic" frame, where if you go forward half a pixel, instead of a full one, the game would glitch in a way advantageous to the player. He also told me it's easily repeatable as long as you memorize where the each enemy appears and are super careful when you try to activate it. He repeated it a few more times before I had to go home.
I was in awe. I had never considered such a thing, being a kid, with a kid's logic; enemies in games just "appeared" either in predictable patterns or randomly, that's how it worked.
After I had a little time to mentally digest what I had learned: I had a full-on video game epiphany: if my character's movement determined when enemies appear, if I carefully control my character's movement -I- can control when the enemies appear: reducing a formerly wild and chaotic system into series of predictable triggers.
It's like I finally learned the special move! The ultimate secret to finally bring down the, up-to-this-point, invincible, undefeatable foe!
I now finally had to will to challenge
that game, which had been gathering dust in it's home in the stereo cabinet next to the TV. It took weeks of hours-long, thumb blistering, arduous sessions of gaming. Much trial and much error, I applied what I had learned. I progressed through the game with a new vigor, and in the process; essentially re-learning how to play video games, replacing my reactionary flailing with careful calculation and a keen eye for cause-and-effect (at least, has much as possible for a fat, nerdy, 14-yearold).
My progress through the game became like a specialized code of movement or a carefully choreographed dance: "... after climbing the ladder to the third floor, jump to the top, move right half-a-pixel, wait for the pumpkinhead to throw the second axe, jump onto the platform while the axe is at it's highest point, run right, slash punmkinhead, run and jump to the next platform, move two pixels forward, wait for the bird that appears in the upper-righhand corner of the screen to fly to left edge of the screen, run right and jump to the next platform, run right three more pixels, duck and slash right at the bat that appears, jump up to avoid the bird again, run right two more pixels duck and slash the bird on it's return, more right two more pixels... ect, ect, ect" (this is roughly four seconds of realtime)
After learning the timing to get past those shuriken-tossing jetpack-ninja, I finally progress to new ground: 6-3, which is no less difficult, but with my refined technique, I make rapid, if hard-won progress.
Now finally, the the showdown: as alluded to in the cinema scene, Ryu must defeat the crystal controlling his father...
...then face the Jaquio...
...and finally the Demon...
...and discovering the abject horror that if you happen to die fighting in this three-stage final boss, you are sent back to stage: 6-1!
[HIGHLIGHT]MOTHERPUSSBUCKET[/HIGHLIGHT]
I almost broke my NES Advantage that day... but my pride was on the line, and I WILL NOT let this game beat me! Fortunately, after my rage has abated, my skills were sufficient for a threepeat, and beat the game handily.
Newer memory: managing to cheese a double time-over victory over Princess Sissy with Shintaro in Matremelee, during the final GameLand lock-in event in 2004.
Actually, I mis-remembered (a lot apparently...).
During the final lock-in,
I was determined to beat Sissy with Shintaro, but it was going badly because Shintaro has no projectiles and GameLand had no A/C (which is serious in Las Vegas). One of the NG.com Vegas locals: Fygee, along with Dash no Chris, Domino-chan, Ancient Flounder, and that other guy (I don't remember if Dinododo and Decpticreep could make it or not).
When I was beginning to wither, from the both the heat and being raped by Sissy's Abobo-in-a-box for roughly an hour, Fygee stepped in, and offered to alternate playing against her, where we would tag-off with each credit. After a while, it was determined that it was best method was to fake her out into doing her saw-kick then jump over and land a wall check

+

, repeating as often as possible without getting nailed, then play keep-away until time ran out.
He managed to pull it off first:
I managed to pull it off later that night, and again on Dash no Chris' AES at EVO 2007, and again, when I got my own Matrimelee MVS cart to play on my cab.
Also, from
the same event: Neo Cakes!