I feel a bit silly having to explain it, I guess the game still needs better writing about the tutorial, I'll try to improve, whatever....

Stuck in front of the red barrel? 

In summary, you can only damage it with fire/heat, go to alchemy system -> ACTION

After you have EQUIPPED it, stand in front of the barrel and hold down the elementary circuit button, by default you use the space bar or the R1/RB, in the tutorial it mentions which button it is

Did you get stuck in the cave?

This is completed by using an ALLOY, i.e. equipping an element to the whip, but first you must find the element "CARBON".

If the place is too dark as in the picture, TRY ANOTHER SIDE, this is a metroidvania! go through a water section and at the end you will find an ACTION circuit to light up the place.

Once you have this light spell, you can pass the dark areas more easily. And finally get the CARBON

Now simply equip your charcoal and destroy the minerals blocking your way!

And that's all, I make this post for whoever needs it, don't worry, I will try to improve the prologue of the final game using your opinions (at least most of them). But for now I will keep working on the rest of the game.