Finding all green stars in Super Mario 3D World.
The final level is a pain imo.
(Didn't 100% though, have to clear all stages with all characters for that, once was enough thank you!

My proudest gaming moment has to be, beating Dark Souls 1 and 2 back-to-back without getting hit, I spent months practicing, failing and failing, but ever so determined to finally make it. I firmly recall my heart racing like a madman when I fought against Nashandra, landing that final blow and feel victory wash over me at last, that.. to me was the proudest moment in all my time as a gamer.

I have most of the games in the draw. If I won I was intending to gift them to others. I guess there is no way to do this as they are not transferable.

I will withdraw my entry if this is the case. In the off chance that I won most of the codes would be wasted. :)

Beating Abyss Watchers in Dark Souls 3.

If I’m being really honest, my proudest moment was probably when I was a child and I figured out how to beat the age check on my dad’s copy of the first leisure suit Larry game. It may seem silly, but that would probably have to be it.

Ah, yes. I found that the hardest part of the whole game as well!

There is one that always comes to my mind first when facing this question.

There was an MMO I praticipated in, called Adventure Quest. I was doing ok, was in for like a year or something, and did some weekly raid on the weekly event.
The final boss was suprisingly hard. And I mean REAL hard. So hard I've never seen.
Being an MMO there could be no save&reload magic, or anything, really.
I said, I can do this, so I chucked down the first health potion. Then the next.
Then the mana potions.
I've tried to imagine the entire battle to pull the most efficient use of my character's abilities.
I've chucked down my last potions, and I came with a full supply.
I've cast my last spell.
In the end, I've faced the monsterous monster, and literaly told myself: whoever hits the other first, wins. And if I miss, he'll land his hit. So this better connects.
And the rest is history.

Turned out, they coded something wrong, and everyone got the highest level boss (mlvl 130).
My character was clvl 30.
I've beaten a boss 100 levels over me.
And yes, the reward-tier was coded right actualy, so all I had in the end was [s]this T-shirt[/s] a trophy-item.

Beating the final level of Z more than 20 years ago.

Probably some match when I played Starcraft multiplayer 20 years ago. I was mostly terrible at it, but I can vaguely remember there were some funny occasions when I had almost lost, but managed to come back again and win (obviously against opponents who also were fairly incompetent).
Hard to think of anything more recent...am not really "proud" of anything done in games anyway, since gaming "achievements" are fairly meaningless. I did recently manage to complete "Return of the Obra Dinn" completely on my own, without looking up any solutions on the net, so at least I could be satisfied that I'm not too dumb for that kind of game :-)

Anyway, I'm not in the competition, my laptop can't run most of the games, and since you can't gift them either, they would be wasted on me.

Proudest Gaming Moment eh?
I got a good one
I remembered playing a Lego game when I was younger. Wanting to play it again. I had to first figure out what game it was. Then once I had figured out it was Lego Island 2 I tracked down a copy over a decade after its original release date and also an old Windows xp laptop since it doesn't run on modern windows anymore. I then completed the game 100% something that I could never do when I was younger I didn't even know how to get past the first level back then. My proudest moment was when I defeated the "Brickster" at the end of the game (The final boss) something I didn't even know existed when I was younger.

Some nice games in that bundle, so sure, I'll try.

But honestly... it's a tough one. I'm not very good at games, but I've managed to beat some tough moments. Maybe the final boss in Star Trek Voayger Elite Force? That was a beast. I really felt great when I finally beat him Prince of Persia Warrior Within had some tough ones. Maybe killing the final boss of Witcher 3 on highest difficulty on my first try? That felt good. Finally defeating the end boss in Hand of Fate wiith barely a fraction of health left? That was exhilarating

Nah. I don't think it should be any of those. Those, and other like them, were great moments, but it shouldn't really be about this kind of "beat something difficult" stuff. I don't really like the competitive streak in gamers, the tendency to measure skill, obsess over beating games on highest difficulty etc. It should be about a different kind of pride. Can we go in a different direction? Find a place where pride and humility meet?

Way, waaay back, somewhere around 1995-6, I achieved something great. I watched in awe the glory of my making. I was playing Dune (the one by Cryo) and I was terraforming Arrakis. I walked its desert before, the infinite horizon of sand, I spent the whole game flying over the endless dry sea of scorching heat from base to base, but now I could walk gardens of my own creation. In the command centre I saw the yellow globe turn slowly green.

I was just a kid. I would not read Dune - the book for many years. I knew little sci-fi before. And now I went through this whole epic story of a distant future, I fought a great war on a planet that was all desert of a scope I could barely comprehend. And I transformed it. I won, and I didn't just defeat my enemies. I didn't shoot a boss. To win, I transformed the world. You bet I was proud. But it was, I think, a better sort of pride than most games give you. I didn't feel like the greatest badass in the universe. I was still small. Arrakis was still huge.

In truth, it's hard to say how exactly I felt back then. How much of the memory is thoughts I project back onto it. Memory is a funny thing like that, and I was jsut kid. But, some 25 years later, I do remember that globe turning green.

Most probably my moment is slightly different than yours. I picked a moment when I bought my very first original game.
It was in the old days of 90s and I was a poor high school student with no income. I can only afford to buy computer games magazine time to time and only read instead of playing :)
And in one issue there was a very positive review for new rpg game Albion. I was totally amazed by it and decided to get it. Since there was no other chance to get game than buying it, I started to spare money. In a few months I finally saved the required amount and went to game shop. Since in those days discounts weren't so common like nowadays I had to pay full price for it.
I still remember exactly my feelings when was leaving a shop with new and shiny box in my hands. Then I had almost sprinted to home to put seed into the computer and start playing...

Since this day I bought many others games, but the feelings of your first game are unforgettable.

Proudest gaming moment was competing, Mast Effect One non Legendary version on PC many years ago with the hardest difficulty setting selected. And without dying after lots of partial playthroughs using different classes and builds. One of the funniest things about Mass Effect before the release was I wasn't much of a fan of the game until I started playing it. And have been hooked on RPGs ever since.

Proudest would probably be finally beating The Legend of Zelda. I watched my brother play through it as a kid, but never could get anywhere on my own. I sat down with the Wii Virtual Console game a few years ago and had a lot of fun playing through it.

Runners Up: Final Fantasy VII (Beating the Emerald and Ruby Weapons). Grand Theft Auto III (Getting 100% Completion). And lastly, hitting 1000 points in Leisure Suit Larry 6.

At first, I was thinking it would be from a Zachtronics games, where tweaking and improving your solution is hugely satisfying, but no, my proudest moment is that "perfect" Into the Breach run:
Customized Squad (Lightning Mech, Rocket Mech and Nano Mech)
Time traveller: Harold
Civilian Saved: 30000
Total Kills: 200
Failed Objectives: 0