I had the idea of, you have 20 seconds to make it. If you do, then there is another section with a different task or a different room, and you again have 20 seconds to do it. If the 20 seconds are over you lose.
Would that be allowed?

I am not rally experienced with developing but if I have enough time I would like to implement that in my game.

For this jam we’re looking for 20 seconds games, not longer games broken up into 20 second sections. You can work within this by presenting the player with one randomly selected level, for instance.

However, we’re not disqualifying submissions that take the approach you describe so you can pursue it if that’s what you really want to do

Im not exactly sure about what I'll try to do so I'll keep that in mind. Thx!