It lasts one week.
Submissions are open from Sunday at 7:00 PM to December 15th 2019 at 7:00 PM
(on my GMT in France)
Honestly i'm a bit surprised (i didnt take part of the 1 button jam) that it lasts 1 week, for such a simple game i expected something like 48/36h, but this is good (especially for beginners). I am looking very forward to this.
imo, a very simple but polished/finished game is much better than a very complex but not finished/polished.
In my opinion, 48h jams are good for IRL jams. For online ones, It's harder to organize with a team, so more time is good.
Also, it makes it so that the jam take place on every different day of the week. So if someone is only available on tuesday and friday for exemple, that will leave an opportunity to participate.
Good luck for your game =)