In middle school, my friend and I built a Top Secret-influenced supers game. I vaguely remember it was called Champions, being unaware there was already a real supers game of that name.
It was terrible.
(Might still have been better than the real Champions.)
More of a hack I guess but in the lead up to Rifts being published I was so stoked about it that I ran a Ninjas And Superspies based series that culminated in the invasion of The Mechanoids and the apocalypse that resulted in whatever exactly Rifts was going to be. It was almost as bonkers as the actual Rifts games we played for the next few years.
I love all the blissfully simple D&D approximations in this thread!
I mentioned my first RPG in another thread – Spy Party, written for Game Chef 2015. It’s a larp-ish game about spies trying to pass on intel at a makeover party by color-coded nail painting.
My first tabletop game was a hack of Monopoly in which you are trying to keep the people* of Atlantic City from being eaten by dinosaurs.
To be better than the real-world Champions, it would have to have been the most comprehensive and elegant point-based game design ever written. Sorry you don’t like it. It’s incredibly, obsessively well-designed for its intended style of play.
In grade school, I used to run a free form RPG with my friend at lunch. When it came to determining if his character succeeded or not, I’d simply figure out the options in my head and make a ruling based on how close to one of my good options he chose.
It…it actually worked. I believe this is because I wasn’t trying to win vs him. I simply tried to judge fairly, that and and we were both super interested to see how far this story would go.
We had a collaborative hack of D&D in high school so we could play Star Wars as there wasn’t an RPG for it at that time.
However my first big solo effort was Versailles for a Game Chef competition
Played a crappy pretend version of Diablo 1 that was a turn based RPG called “Deeblio”. It was absolutely not a real game but just a way for me to pretend to make a game. I had “snowman” as a class!! 8 year old me also had a spellbook, which I’ve been meaning to scan one of these days.
Outside of that I made a more fleshed out MUD-like turn based video game in high school very much inspired by D&D and Baldur’s Gate. I ended up getting full points for my final project 
Definitely in the “not sure if this counts” category, but:
In high school I designed a LARPy game after watching The Thing. The rules were simple and designed to be played amidst everyday life.
One person started as the Thing; everyone else was human. When a human was alone with the Thing, the Thing could reveal itself and turn the human into a Thing.
There was also a “flamethrower” — a red wristband that protected you from the Thing. The catch was that any human could ask you for it and you’d have to give it up.
The game ended when everyone had become the Thing.
I never actually got to play the game — none of my friends thought the idea of constantly being paranoid around each other sounded as fun as I thought it did.
The first RPG I’ve technically finished is a simple one shot LARP experience a friend and I did specifically for a Holloween retreat.
I’m not super proud of it just because the subject material is so over the top dark I don’t feel comfy sharing it anymore (it starts with a content warning for suicide and dark secrets).
The game involved seedy characters revealing darker and deeper secrets about how they’d wronged others, with the only release being their death. 
The people present at the retreat appreciated the experience but it was very intimate and included a lot of aftercare. I’ve learned a lot since then.
I once hacked Rifts to run Warhammer 40,000. I have no idea what I was thinking. The first game I wrote and played was a Storyteller hack to run Rifts, just to bring things full circle. That actually wasn’t bad. There was an sliding scale of cybernetics and magic for your character so the more of one you had, the less of the other you could get.
I’ve made and shared a number of small pieces of content for existing RPGs, but the first “proper” RPG I’ve made is probably Storm Riders!, published in Codex Joy 2 (even if it’s a hack of a hack of a hack, I would still call it an RPG.
For the 2017 200 Word RPG challenge I submitted On Divining Oneirography. This is definitely something that I’m “not sure if it even counts as a game.”
Dearest Friend,
There are men after me. They have been watching me for some time. I haven’t much time to write these instructions, so please forgive the erratic nature of my handscript. I shall send you a clue to my whereabouts, but it must be encoded and obscured by esoteric means. What good fortune that there are those amongst you with the ability to decipher my message!
Have your oneirographist lie down upon a chaise longue. She must close her eyes and prepare her spirit for transsomatic travel. Provide her with a colored drawing utensil and place a sheet of white paper beneath her wrist. She must clear her mind of all distraction. As she drifts into a meditative state, her hand will begin to move in a swirling scribbling dance. Truly, the drawing of dreams is a beautiful thing to behold.
When thirty seconds have passed, wake the dreamer from her trance. Instruct your medium to take a black pen, and, with guidance from the spirits, interpret the image embedded within the astral abstraction by tracing the meaningful patterns within. With this, my location should become clear. I beseech you, make great haste!
With Sincere Regard, your ally Maylisbeth
Not counting several clunky hacks to play Star Trek (no, Ars Magica wasn’t very good for that), the first one I found was “Little Fears in a Kimono”. I have no idea what went through my mind, but I wanted to play around with PowerPoint (which I had just gotten for the first time), so I designed an rpg about Mangas and responsibility.
It was about kids who had special powers or abilities and who had to defeat a world-destroying menace, like those you might see in mangas or animes. The mechanism was a simple token mechanic - start out with 1-3 token that you can use to defeat a challenge. You can generate new tokens by failing. That was the core mechanism with some needlessly complicated and dysfunctional mechanism for juggling final narrative rights. After two hours, I had a not-quite-workable game, no great insight into PowerPoint after all and a lot of giggles.
Not counting a hack for Pathfinder to bring in Duel of Wits, my first game was Magicians and it’s the game I’m still most proud of!
It marries the magical school genre with learning a language in real life and it all meshes so well. It’s a little clunky and it never made any money but boy do I love it.
My first game was a hack of Palladiums TMNT to play Borribles. It did not went well and was never finished.
The first “finished” game is my Weird West hack of Blades in the Dark, called “A Fistful of Darkness”. It’s already better looking than my Borribles game (= it has more than one picture in it) and there are actual people playing it, so from my POV it’s an huge sucess 
in seventh grade I made this video game for a science fair project.
I still have it. It was heavily influenced by an old BBS door game called Legend of the Red Dragon. I wrote it in QB4.5 and it won first place at my schools science fair and placed second in the regional. I was very proud of this thing then. As an adult its pretty cringy.
As a kid, I designed a lot of board games. But the first RPG I ran was also a bit of a hack, reskinning All Things Truly Wicked (a 2 page RPG about childhood fears) into a mystery game set at a boarding school beset by creatures from Greek mythology. I ran it for my younger siblings and catered to their genre interests (the Gotham Academy comic, the Percy Jackson series). I also Photoshopped away the pentagram that originally appeared on the character sheets so they wouldn’t be too scared to play!
The first RPG I ever made was a Bloodborne hack of Urban Shadows called Yharnam Shadows. It’s quite a light hack, but it is a wonderful way to explore the Bloodborne lore, and one of the best games I’ve written. Most Bloodborne games focus on the combat, and lose a lot of what I think TRPGs can bring to the subject.
This game is set before Yharnam descends into the state you find it in during the events of the video game, and focuses on the factional conflicts in the city.
The first game/hack I ever dreamed of was an expansion to the boardgame Clue. In my mind’s eye it included an expansion to the board which would add new rooms; there were other things added on too. That was 40 years ago.
The first real game-thing I made was a fairytale-fantasy RPG with a simple d6 mechanic. But it’s lost to posterity (i.e. I don’t know where it is). It wasn’t good.
When I was 10, in the winter of 1999-2000, the Dungeons and Dragons movie came out.
I didn’t see it, but my neighbors down the street, Sam and Max, did. Their dad had played D&D a bit in college, and described the game to them. Sam wanted to play. So he described it to me, and my next door neighbor Patrick, and our friend Clay, and Clay’s dog.
None of us had ever seen a D&D book.
Some things were lost in the game of telephone.
Sam was DM, because he was oldest. The rest of us grabbed sticks or spars of bamboo from the backyard. Short sticks were swords if you wanted to be a fighter. Long sticks were wizard’s staffs.
We’re out in our backyards, in the woods behind our houses, in the park down the street. Sam says we’re trying to get through a dungeon because Paradise is on the other side. He describes the room we’re in. Any monsters or obstacles or traps or objects there.
We’d tell Sam how we attacked the monster, usually by saying where on it we attacked. He’d tell us the monster died when he judged we’d attacked it effectively enough times. Tough monsters would usually only have a few, non-obvious weak spots, and take a lot of hits. Weaker monsters we could just kill in one blow. Sometimes we’d get several at once!
And then Sam would tell us how the monsters attacked. Usually he’d say it bit us in the arm, or the leg, and then we couldn’t use that arm or leg until we were healed. We had to drop our stick or hop around. Tougher monsters would attack more often.
Treasure was usually potions, scrolls, and one-off magic items. I don’t remember too much about the details, but I remember we found a scroll of Rainbow Blast, once. (A descendant of Prismatic Spray, or Sam’s invention ex nihilo? I’ve often wondered.) It saved our butts against some Apple People. There were a lot of them, and you could only hurt them by eating them, but by the time we figured that out, we had a lot of useless limbs and there were still a bunch of them left. The Rainbow Blast took 'em all out!
Then we’d move on to the next room, wandering over to a different yard or area of the woods or park.
When it was time to go home for dinner, Sam would tell us whether or not we’d made it through the dungeon to Paradise.
A couple friends and I stayed up late one night making “The Tick RPG” based on the original comics, which were … slightly weirder than the TV shows, I think. Our skill list included "Dewey Decimal, Advanced Dewey Decimal, and Doorknob Operation (which playtesting confirmed was indeed an interesting skill to avoid taking).
