It's a game jam, but themed around the Vinesauce Twitch channel.
You have a certain amount of time (1 week in this case) to make a game based on the theme. It'll then get judged and ranked alongside a bunch of other peoples' games. The best of the best will then be played on-stream at some point. Hopefully.
It'll be revealed when the jam starts. You can see when that will happen using the big handy countdown timer at the top of the page.
Failing to adhere to these rules will get your submission disqualified until the issue is resolved.
At the end of the submission period, the judges will vote on each submission for Entertainment, Creativity, Visuals, Audio and Theme Use. These will be averaged by Itch.io's usual system to determine the final ranking.
You can discuss the jam, ask questions and find teammates in the community tab built-in to this jam page. There aren't currently any plans to set up a public Discord server or anything similar for ShroomJam.
Vinesauce Website | Link | Vinesauce YouTube Channel
PotaJoe
Vinesauce
Bees With Chainsaws
Kekulism
SinCityAssassin
The Monotonist
Wrinklynewt
McDanooj Joey
Logo Font is Typesauce by Maxi Gamer
General page design based on the Vinesauce website
Jam page, logo and setup by PotaJoe