This jam is now over. It ran from 2023-01-30 09:00:00 to 2023-02-12 22:59:00. View 17 entries

The challenge

As if creating games within a 48-hour time window was not hard enough, we're inviting you to take part in a challenge: create an online multiplayer game using coherence during Global Game Jam!

To ease your mind, we know for a fact it can be done.

The deal is simple. Just take part in Global Game Jam during its normal schedule, online or at your favourite local site, and make a multiplayer game using coherence.

Then submit it here too, and we'll make sure to reward the best ones.

$10,000 up for grabs

In addition to the personal gratification of giving yourself this extra challenge, we’ve decided to reward the most innovative multiplayer game ideas with $10,000 worth of prizes!

If that sounds like something for you, sign-up to the jam on this very page!

Help & resources


To sign-up for the game jam:

  1. Click the “Join Jam” button above
  2. Make a game at Global Game Jam using coherence
  3. Submit it here too!

Key dates

We align with the schedule of Global Game Jam, but we allow for a little extra time to submit your game to our challenge, so you can iron out details or fix some last-minute bugs.

  • 30 Jan: Global Game Jam week begins
  • 5 Feb: Global Game Jam ends
  • 12 Feb: Submissions to coherence challenge are closed
  • 21 Feb: Winners are announced


You can read the rules of the contest on this link


What is coherence?
coherence is a network engine, platform and a series of tools to help anyone create a multiplayer game. Our mission is to give any game developer, regardless of how technical they are, the power to make a connected game.

coherence offers an SDK for Unity that allows to very easily sync the state of GameObjects across multiple clients, to make them persistent across game sessions, and to create game logic that is simulated on the server. Or to do all these things together.

To learn all about what coherence can do, check our website, or to go more in-depth jump into our documentation.

What is the Global Game Jam?
Please refer to the Global Game Jam FAQ.

What software or assets can I use?
We only ask you to use coherence (which implies using Unity). For the rest, you can use any third-party plugin, Asset Store assets you own, or custom code you wrote before.

Can I bring a game already in development, and add multiplayer to it?
No, the game needs to be created as part of Global Game Jam.

Do I own the games I make?
Yes, totally.

Do I have to share the source as part of my submission?
No, we only require you to submit the game build here on However, the GGJ guidelines ask you to submit the source of your project on as you submit your game during the Global Game Jam weekend.


All submissions
Browser playable (7)
Windows (8)
macOS (2)
Linux (2)
Android (1)

No submissions match your filter

A very simple "gardening MMO" made with coherence and Unity. Collect seeds, plant them (and yourself) and collaborate!
Play in browser
A top-down slasher game filled with horrors.
Math Bullet Hell
Play in browser
In "Aldaron - The Lord of Trees," players control an Elf defending the Ancient Trees Roots from evil mushrooms.
In this online multiplayer game, compete with enemies to capture the purple decryptable targets
Realtime multiplayer, where you can play as nature and defend the planet from humanity or play as a human and destroy it
GGJ 2023 Multiplayer coop arcade game about brewing potions with conflicting roles
Musical chairs with violence
Four concepts of "roots" fight each other in an all-out brawl to become this GlobalGameJam's chosen theme!
You're a bumblebee on a mission to save the tree of balance. Collect potatoes & feed the roots w/friends.
Play in browser
Defend the last flower from the evil tractors. Bring your friends because this is a community! ... garden
Play in browser
Root. Expand. Conquer
Play in browser
Top-down multiplayer ant-warfare. Recruit ants (doesn't work) and dominate the server by having the biggest colony.
Play in browser
A picture puzzle WebXR(XR:AR+VR) game.
Play in browser