After almost 2 hours of thinking, I have locked down my concept.
I will be working on an Unfolding game, centering around the research for the Eternal Life.
As you work to reach your goal, you will need to find ways to gain money to make it further.
(Further information in the pastebin: https://pastebin.com/vazmu2H0)
As previously mentionned, I am streaming the event on my side. (Although I am currently muted)
After one-hour's thinking, I've finally got my idea about the theme Alchemy! So it's basically a 2D parkour game, which obstacles and enemies are elimiated with potions - you may have known already: potions need to be produced with your mastered alchemy skils
So here's my gameplay design, if you are interested:

I finished the player/weapon animation a while ago and I just finished up the first tileset!

Did it change?

Could be worse. Or could it?
the title? i would like to know wha the actual theme is now
Due to a last minute change in the votes, we completely messed up our announcement video! Here's the updated version:
The jam has started! From now on, you have exactly 48 hours to make a game from scratch and submit it in the Solo & Team divisions. For Unranked entries, submissions will be left open one more day.
Happy jamming!
First Jam ever.
Not ready.
Although, in.
Edit (now that the infernal pressure of the countdown is over) :
I will do something in Python 2.7.
It is going to be a console/terminal/whatever-you-want-to-call-the-black-box-with-a-blinking-cursor game.
I will eat thaï food whilst working on it.
This is live from the nightdesk of a three star hotel in Paris.
Good luck!