Obviously many of us ended up claiming multiple "Only One" elements, but I imagine we all started from one core "Only One."

For my team's project, the original core "Only One" was
"Only turning in one rotational direction, but in 3D."

I figured it'd be used for a non-euclidian racing game, but as we did a genre-brainstorming exercise with our favorite Only-Ones, someone thought of combining only turning one way with a flight genre game and suddenly the game we made started coming together.

Now our list includes: one rotate direction, one engine left, one engine remains, one attempt to land, a world-war one plane.

What was your team's initial/core "Only One" and how did it evolve?

For our game, https://portrait-prophecies.itch.io/while-the-whole-world-laughs, "only one" is in reference to the protagonist being disjointed from existence by their lack of memories, and their final choice in the story.

My "Only One", was to have only one color in the world. Depending on the current selected color, the properties of the world would change. I wanted to add some more interesting puzzles where you would need to time switching between different colors, but didn't have enough time to figure out a good design and implement it :p

This is a link to my game if anyone is interested in checking it out: https://itch.io/jam/gmtk-2019/rate/461706

Also, apparently my game doesn't even work. I've tested it on Chrome and it seems fine to me. Would appreciate it if anyone can confirm if it's not working for them too. 

Originally my plan was only one colour, which I've stuck to but also I suppose only one screen could count too :)

https://itch.io/jam/gmtk-2019/rate/462582

Only one tower! For a tower defense, that is. Apparently, not very original at all, hahaha, but i tried to take all the juice out of the concept as possible. It's an evil teleporting tower! Just fun. Also loved to make the animations for the towers, the melting and stuff, 

I have played other "Only One Towers" (even with the same name) and it's fascinating to see other people's take on the idea. Seriously, it's like 20 of them out there.

Here is mine! It's kinda really hard, i challenge you to beat it, haha  https://stopsignal.itch.io/only-one-towergmtkjam

i'd also recommend the other ones, seriously! 

https://matheuscunegato.itch.io/towerbag this one has a lovely artstyle, for example, check it out!

I honestly thought back to this super Mario 64 speedrunning video where this dude talked about how to beat the game with the fewest possible A button presses. More specifically how to beat a certain level without pressing a more than once. The fact that there was so much depth in deciding when to press A and what actions were available to you based on whether or not you were still holding it down showed off how versatile Mario 64's movement really was. I went with the idea of being able to press each button only once because I thought that I could take a basic platformer, but force the player to always be considering what actions are available to him, and which buttons he will need to save for the future.

Check my game out here, it's called Full Press and, even though I don't think it's a winner, I think I made a good attempt at exploring the idea.

My only one is my Grandma who died less than a year ago. I did this game about her <3 It's in french but trad is comming !

https://itch.io/jam/gmtk-2019/rate/462187

My game adhered to it's core "only one" theme to a T. Even down to the name of the game. Every weapon you use has only one use before breaking, only one durability. 

For me the first thing that came to mind was "One Shot, One Kill" so I built my entire game around that idea. 

https://bigfraudbigfraud.itch.io/gmtkjam2019

My "Only One" was one leg because I thought it'd be funny to have an fps with a constantly stumbling character, but it's was too disorienting to play so it ended up becoming a third person platformer instead. Because of time, I couldn't really add mechanics that I wanted (like shooting) so I took a different direction ;)

Can't spoil it, if you're interested you can give it a try!

https://itch.io/jam/gmtk-2019/rate/462200

For It's Rude To Point, our team's "only one" was interpreted as "only one finger". With one interactive finger, you would interact with on-screen objects by either grabbing or flicking them. 

We actually stuck very closely to this concept, but instead of just making it a point-and-click sandbox game, we decided to spin it into a series of short action minigames that would all involve the finger in some manner - very similar to WarioWare or Dumb Ways To Die.

It'd be much appreciated if you could give It's Rude To Point a try, and possibly a rating too! It's WebGL-based, so you don't have to download anything to be able to play it (aside from the Unity Web Player plugin).

https://itch.io/jam/gmtk-2019/rate/461113

I did "only one" button where clicking the mouse does multiple different mechanics.  Then, just to be safe, I used "only one" color on top of a black background for the graphics.

For my project I used a few. Only one life. Only one jump. And another "only one" to anyone that makes it through the game (If you finish the game you will understand). I only had about half the time to work on it because I couldn't take time off from my job, but I think I got the theme across pretty good.

This is my first game jam and I made a game called bounce shot: https://itch.io/jam/gmtk-2019/rate/461622
It has one button control, there's one player, one enemy, you technically have one health, and it plays on one screen.

You need to kill the enemy by shooting your bullet at them, and bouncing it off the walls to get around obstacles. You get more points, the more times the bullet bounces before hitting the enemy.

I'd also recommend this game: https://itch.io/jam/gmtk-2019/rate/461470. Lots of fun, and a cool idea.

My "only one" started with only one weapon on a maze...

... then I saw that the weapon could be the player's life as well!

https://itch.io/jam/gmtk-2019/rate/463767

You start in a ghost state, nothing can attack you and you can't attack anyone. When you find/get your life, then you have to sacrifice it to turn surrounding enemies into ghosts. Whenyyou do, you go back to the start, the life stays where you were and you have to find it again, but now there are ghosts that can kill kill you.

For our project A Cat Named Shmup, we did "Only One Bullet".

Since in most shoot 'em ups you just fire an infinite stream of bullets, it provided a really interesting design challenge to only be able to fire one bullet! Our solution was that when your bullet collides with an enemy, the bullet splits into another bullet causing a chain reaction effect.

It's really interesting to see how limitation can drive creativity!

for my game, "Only One" is a shooting game with only one bullet. In my game, the player has only one boomerang and can only throw it once at a time. So they have to think carefully before throw it because they will be vunerable after throw it. Here's the link: https://itch.io/jam/gmtk-2019/rate/46355

Ours was only one platform. We had very good ideas but we went with this one because we figured out we could give the player the control of the platform, and so he'd have to be aware of the movement of both the platform and the character.

In the end, we got a pretty solid game imo. You're a surfer astronaut, and the platform is a hovering surfboard. We came up with some cool mechanics, for example, there are satellites that fire a laser beam that kills the player, but they have a button in the back that the board can press in and the laser turns off. We tried to make a WebGL build, but it didn't work very well, so sadly, you have to download it, but we'd appreciate a lot getting some feedback!

https://itch.io/jam/gmtk-2019/rate/462969

Our team did a visual novel about Social Anxiety where you are only capable of talking to people only once. Went smooth and ended up better than I expect. The team was great and I had tons of fun Voice acting.

https://itch.io/jam/gmtk-2019/rate/463328

For mine the intention was Only One Jump, but I ended up having Only One Screen (per level) and Only One Platform https://itch.io/jam/gmtk-2019/rate/460806

In the past I've been guilty of entering jams with an idea in mind and then altering it to fit the theme, but this time this time my whole idea came purely from the theme. I guess that makes it a good theme 😁

My game is Broken Robot and the only one at the base of the game is that the game is a puzzle platformer where you can only press each direction one time per level. There are other "Only Ones" in the game, but at the core it is the controls that I made the game around

https://itch.io/jam/gmtk-2019/rate/462219

Our game is an 2D action/survival game in only one room. But real the "Only One" of this game is the Color :)
https://becher.itch.io/ligth-them-up
Have fun ;)

There was only one door in the original idea. But then one room appeared... then one minute... one nightmare.... =D

https://itch.io/jam/gmtk-2019/rate/462518

https://itch.io/jam/gmtk-2019/rate/461964 For my game, it was Only One Dimension. There seem to be lot of entries in this theme though, :)

Mine has many "only one things" but has something I didn't find in any other: 2 players. The first ide was having only 1 unit.That's why I called it "One Man War" I latter added a couple more only ones:

You also only mine one resource (wood) 

You have only one building

You have only one goal, destroy your enemies 

https://aleconde98.itch.io/one-man-war

https://itch.io/jam/gmtk-2019/rate/459177 Only one button for us (mouse button), and only one..something else (that one you'll have to play a few seconds to see).

For our game "Only One" was only "One Arrow", that was it. That is the core "Only one" at Unusago. Here is the link if you guys might want to take a look at it: https://itch.io/jam/gmtk-2019/rate/461869

Our game, "1Minute" has several (ironically) only one elements, with better or worse execution.

The original premise for our project was to use one button and make a rhythm game with it. In the end after brainstorming we ended up making a game where you type using a telegraph.

The character is alone on his room. He has one arm. He has a telegraph and a morse code manual, but can only use one at a time. The color palette is centered around one tone. The music you hear while playing is designed around one note and uses only C for the melody. The premise is kinda based on WW1, but we opted for using an aseptic war, with ni real bands or anything.

Ah, also, you have to send one message and have one minute to do it. If you do so, you stop a chemical bomb from being dropped on your country.

My friend and I's project was originally  conceived as a "single-stick" shooter (a take on twin stick shooters) with only one stick and one projectile. At first we imagined the player as an archer that would move themselves by firing arrows, but that didn't make a whole lot of sense. We ended up adopting a sci-fi aesthetic, so the idea of moving the character with the projectile's recoil was on the page again. As we built, more and more elements fell nicely into the "Only One" theme. We have one persistent boss enemy, one stage, one life, etc.

My game: Safe Place. A platformer where you only get to attack once per room.

https://itch.io/jam/gmtk-2019/rate/462235

For me the "only one" means, that only one specific side of your dice will grant you access to the next level.

https://itch.io/jam/gmtk-2019/rate/462667 

Title says it all!

Our game is based in a Submarine around the fact that you only have a single system active at a time! Plays around the concept of Minimal Information!

Comments, feedback and ratings appreciated!

https://kaiskii.itch.io/help-im-stuck-in-a-submarine

We went for "Only One" pilot in a fleet of a thousand ships.

Then we added "OnlyOne" Enemy.

The ships that have no pilot can only do very basic actions like fire blindly, drop EMP or flee. the piloted ship can order those actions to nearby ships.

The enemy is a planet like ships that you have to "dig" to reach the core and kill.

The game is called OneOnOnes : https://itch.io/jam/gmtk-2019/rate/463229

Well, I have many "only ones":
- the original is: only one button (LMB)
- the others: only one type of weapon, only one type of enemy, only one level (but these are not intentional, just the consequences of the time limit :D )

No Exit: https://itch.io/jam/gmtk-2019/rate/431948

One button fast paced plat-former, one direction, one sprite, one background, addictive swing mechanics,  cool graphics and  sick beats and rage enduing feature.   

1 button, 1 sprite, 1 enemy/boss. All those things where mentioned in the opening video, so I feel kinda uncreative. -.- Turned out ok though I think.  https://sleeper-games.itch.io/mech-revenant-input-one

“Together as one” I wanted to play with the idea of “one” without it being a singular thing. In my instance a flock of bird coming together. 

https://pitman.itch.io/just-pidgeon

my only one was to have only one room. not very creative, i know, but i think the main mechanic of attracting and repelling only one of the colours could have made a pretty entertaining game: black and white

(could have made because i haven't figured it out how to implement the main mechanic unfortunately) 

Only one wheel (and horn).  It was a bit of a cop-out.

https://itch.io/jam/gmtk-2019/rate/462253

We had a lot of ideas but the one which got stuck was only having one arrow which you have to pick up again. Or some sort of disc (Tron movie like). But then we had the idea for a top down shooter where you can only use your weapon onces. So, you only have one shot.

Due to time limitations we also only have one level you play in :D

We spend some time on polishing the game to make the play experience better and more fun ;)

If you are interested check it out here https://itch.io/jam/gmtk-2019/rate/460283

We used the theme of ONLY ONE for our character. The game takes place inside his head and he's the only one. He talks to and fights with himself.

If you wanna check it out we'd appreciate it. It's playable in the browser and on Windows with a keyboard.

Link to the game: https://late-panda.itch.io/head-ache

Ours is a 3D Unity game:
You wake up alone in a dark mansion with only one lightbulb.
You cannot leave the place, yet something seems to lurk in the dark. Is it after you? Probably...

Play the game: https://vonrickroll.itch.io/tread-lightly
Rate the game: https://itch.io/jam/gmtk-2019/rate/461550

I used 'only one color'. There's literally a single full-screen color visible at the time. Communication and telegraphing is all done by color-fading and sound design https://itch.io/jam/gmtk-2019/rate/462105

Can 'see'/shoot in only one colour palettte.
...well, strictly it's just harder to see the wrong-coloured entities/bullets, game would be impossible otherwise. And I might have cranked the difficulty up a bit too much, whoops~
Proooobably a bit too loose with the theme, but I couldn't get past the idea once I'd thought of it ^^;
Any critique would be appreciated~

we made a local co-op 2d action game where only player can move at a time so you need to communicate a lot.

My game Echolocation features "only one" of the five senses. You have to navigate puzzles solely using your sense of hearing.

Our "only one" was a only one button with various mechanics.Here is the link:https://itch.io/jam/gmtk-2019/rate/462703

My game is a Metroidvania, but with only one upgrade - a grappling hook. You learn different ways to use it throughout the course of the game, allowing you to access new areas. Here's the link: https://python-b5.itch.io/grapple. I'd appreciate it if anyone played and rated it!

Only One Rectangle with paints)

Simple, colorful platformer)  I would be very grateful if you have a few minutes to play my game)

Game: https://bloodpirat.itch.io/only-one-rectangle
Rate: https://itch.io/jam/gmtk-2019/rate/460625

Only one button. 

You can play it here:

https://itch.io/jam/gmtk-2019/rate/463337

We made the whole game around the "Only One" theme.

• The character looks like number 1
• The goal of the game to turn every 0 block to 1
• In case you hit the block twice you die

https://joysquid.itch.io/run-one

Our idea was to make a 2D Rogue Like where all the values of the game were dictated by only one value, the "life" of the character, in the game is know as the value. So your life it's not only your life, but is also your attack and  your money . But not only these, because the attack, life and  speed of the enemies also scales with the value. It was a really fun experience to balance all these elementes with only one value, so a lot of mathematic equations where use hahahaha. 

If you want to probe the game there it is :  https://rogue-one.itch.io/rogue-one
And the submision page : https://itch.io/jam/gmtk-2019/rate/461305
Any feedback will be really appreciate, thanks :D

I was a bit cheeky with my idea. ;) So there's a whole crowd of 50 friends and the game ends when there is.. ONLY ONE. Would love it if you guys played and left a rating or a comment! 

https://itch.io/jam/gmtk-2019/rate/462221

I did "Only one jump" and then doubled down with "Only one thing that moves". Also the main character is trapped alone on a space station.

There are, incidentally, two endings.

My game is about stopping time for 1 second. If you want, you can try it out, would appreciate it: https://itch.io/jam/gmtk-2019/rate/461675

My Only One was hacking systems using only one button, as opposed to 2 people power-typing on one keyboard, as is tradition.

We decided to create something funny or unusual, and the idea for "Only One" that we came up with was "one shoe" and object throwing game mechanic. What I meant by one shoe is that the main goal of the game is to find a shoe which was lost while wandering inside of an abandoned building. The object throwing mechanic fit the theme quite nicely as well, because the player is able to damage an enemy only once with one object.
Check out the game if you're interested!
https://itch.io/jam/gmtk-2019/rate/463156

For me, worst than death is that ONE TINY MOSQUITO buzzing next to your ear in the middle of the night. Keeping you up from sweet sweet sleep. I really don't know who my game is for... https://mikeyren.itch.io/onlyone

For me, only one was literally only one, I used the number 1 for entire game, points and power-ups. When u take a power-up, fow example your speed goes from 1 to 11 immediately. But same thing happens to your score too. So you need decide carefully while taking a power-up. They are a little much rewarding :D Here is the game, you can play and rate it!

https://itch.io/jam/gmtk-2019/rate/462865

My "One" is a flag, a blue flag.  You play as a little blue guy from a very blue land. It has been taken over by evil red guys, who have committed the horrible crime of wearing a different coloured shirt from you. What's worse is they have planted their repugnant red flags all across your beautiful blue land! This cannot stand. You will not rest until every red flag has been captured, and all the land secured under one flag, the one true flag, the blue flag!

https://itch.io/jam/gmtk-2019/rate/462780

My "Only One" was "Only One Resource": Hearts. They're your life, ammo, and timer. I also wanted to add dashing with the hearts being stamina, but I barely made the game as is in this timeframe.

Click HERE to play the game: HeartGame

I game that you can ONLY play ONCE (it is actually a meta-puzzle-game)

https://itch.io/jam/gmtk-2019/rate/461276

Only one developer, only one day (sigh), only one dimension (at a time)

https://doctormikereddy.itch.io/thomas-was-a-line and https://itch.io/jam/gmtk-2019/rate/462856

Can only move in 1 direction, entire game including menu's and level built into only 1 Unreal level.

Our game is build around "Only one damage" or "Only one strength" concept.

We came up with a pretty cool damage effect. It's a lot of fun. And I still stuck at level 18.

https://santazaaa.itch.io/hyper-slash

Originally I was planning to make a mixology game where there was only one drink you could make that wouldn't cause your patron's head to fall off, but the files all got corrupted and I didn't have time to finish -_- - so I made a crafting game, Decrafted (https://itch.io/jam/gmtk-2019/rate/463986) where the objective is to craft your way down to one item rather than up to as many as possible

For my game If (https://itch.io/jam/gmtk-2019/rate/461616), an Gameboy RPG game, started with: one action button, one character and one place.

In the end finish with one action button, one character, one place, one enemy, one NPC and one battle.

We made a two-player game called Cyclopia featuring shooting  with only one eye. Literally with one single eye you could not perceive the depth. But you can estimate the distance of the bullet from other hints to bounce off back your opponent like Genji.

I did one huge map xD https://itch.io/jam/gmtk-2019/rate/460859

I did  a text adventure titled "Only One Day", where you live your final day before the end of the world! Jolly, right?

https://brownseededbread.itch.io/onlyoneday

For my solo roguelike project, the only one thing was only one item in inventory :D

Our two person team dug up a rough concept we'd been kicking around but never done anything with. "You had ONE job" is a multiplayer, arena/horde based game where you can only do a singular thing. Shooting, or looting (we wanted to add "defending/healing" but ran out of time). The idea is that you can't accomplish anything on your own. If I keep working on this I want to improve individual player scoring and maybe to end game callouts (Like Overwatch in its voting) and implement the missing class, and generally improve the feeling of you doing a singular thing and playing a role in a larger team.

https://itch.io/jam/gmtk-2019/rate/461546#post-854292

Here it is if anyone wants to take a look, be warned that controllers and multiple people are kinda required to get any kind of experience out of it. Probably not the best for a game jam game but we're endlessly inspired by couch co-ops like Overcooked and Ultimate Chicken horse.

"LASER" As the minimalistic title of my game suggests.

https://guillemsrr.itch.io/lsr

I wanted to pick an idea that would be seemingly impossible with "only one." I ended up doing a text adventure with only one word, and I think it turned out pretty well! https://itch.io/jam/gmtk-2019/rate/461221

In Whiteboard Arena my "only one(s)" were: one vs one with one keyboard, only one action (jump), only one screen, last one standing.

https://itch.io/jam/gmtk-2019/rate/461347

For our game, a maze with only one exit: https://itch.io/jam/gmtk-2019/rate/463810

Sp00ky game where you have only one second to see at a time (lightning strikes)!

https://itch.io/jam/gmtk-2019/rate/463099

For me it was make a platformer with 'Only One' thing to climb. I wanted it to be a creature, but ended having to settle for on massive and complicated wall instead, i learned a great deal about design in the process!

https://newkryptonite.itch.io/the-lonly

After writing 3 pages of ideas and sketches I picked the funnier one that would create more mechanic based on something very simple: Only one eye, leading to "half the eyes, half the screen" mechanic 

https://itch.io/jam/gmtk-2019/rate/460908

I couldn't decide about my only one. So, in my project I used movement in only one direction and only one button for control. Also I tried to use only one color, but actually there is at least two of them: background and foreground. So my game is black and white.

In Ninja On A Budget , you only have a single shuriken to defeat all the enemies!

So you must retrieve it from the corpses after each use... Check it out!

My project was about the last One in a world full of evil Zeroes, and had only one core mechanic, turning on some power switches! These are the little guys

We'd love to have you guys give it a try!

https://itch.io/jam/gmtk-2019/rate/463638

My game is a platformer that uses only one button to control everything.

Mine (https://h-labs.itch.io/only-you) was you being the only thing in the level (aside from the goal). Once I read the theme, I thought "how could you complete a level if you're the only thing in it?" and ran with it.

Through a fun twist of fate, I also ended up with one-button controls.

For my game, "Only one" is the bullet, the minutes and the enemy. 

In the game there is several pnj but only one is the enemy you have to find him in 1 minutes and shoot him with one bullet 

https://itch.io/jam/gmtk-2019/rate/460819

When I heard 'Only one' I immediately went to 'THERE CAN ONLY BE ONE' and the elimination aspect of it, going from having a lot being whittled down until there is only one(or almost only one anyway). Thinking of it like a single player battle royal or a musical chairs like game where you start up controlling a load of characters, until the environment reduces it down to potentially only one as you sacrifice multiple character to solve puzzles to save that one.

From that I swapped musical chairs with zombies that would slowly assimilate your crowd, and while I deiced not to be a stickler of forcing the player to have to reduce there crowd to one person to pass the level, they only needed one person to survive to win. Apart from that, I just tried to keep everything minimalist, colors are mostly all green, all the charters act as one and the like.

My game a quick to play zombie survival puzzle game; https://itch.io/jam/gmtk-2019/rate/461074

For my submission I tried to get as many mechanics into one button as I could.

I made a 2D skateboarding game and I was able to fit jumps, grinds, flip tricks, grinds tricks  and manuals into my only button.

My game's original "Only One" was to create a set of puzzles that required only one key press to solve. And that remained true in the final product.  What did evolve though was how much I wanted to push that central gimmick. I came up with all kinds of weird puzzles by the end that still stay true to the gimmick but also (hopefully) changed the player's perception of it. 

Unfortunately, some of the early puzzles I designed were too obtuse for players who can't read my mind (whoops!). The latter puzzles seemed more intuitive in testing, but my biggest regret of the jam was not revising those introductory levels (the answer to the ladder puzzle is "M" for anyone who wants to check the game out).

https://itch.io/jam/gmtk-2019/rate/461968

My entry's "only one" is the player's only one ability, which is to jump (more than once, though). And, also, the game's playable with only one button.

I intended to have more stages and a recurring boss that you would have to fight in different ways each time (and an one-legged character for extra "one-ness"), but the deadline lazyness struck me hard. Still, I'm glad I managed to submit something in the only one (HA!) Game Jam that I participated.

One hand gameplay, with one input. And.. there is 1 hand model  in game. It is just a simple platformer that allow to play like traditional arcade shooter moving at fast pace, zipping through levels. I learnt a lot of new thing from this gamejam within short period of time.