Any idea how i can do this?
I think for a Sonic game you are going to need to use the physics behavior. I don’t have much experience with the physics engine in GDevelop and not sure what the limitations are, but what I would try is use a circular object controlled with physics as the player. Make it invisible, and make the Sonic sprite to follow this circle. I think it should definitely work with the slopes and jumps.
Not sure about making nice curved slopes though. I don’t think it possible to use custom collision shapes with the physics engine, I think you can choose only circle or box so you might going to have trouble making the curves. But I could be wrong.
In case you can make the curves, regarding the first image what I would try to do is make the curve from 3 or more parts and simply, enable and disable physics on the parts. So when Sonic coming from the left, physics is disabled on the left part of the curve so we can go in and when we reach the top, you can enable the physics on the left of the curve and disable it on the right and this way, we can leave the curve on the right.
Not sure if it helps, I can’t be more specific unfortunately as I don’t have experience. In case someone can offer you a more detailed solution, hopefully going to comment. I would be also interested to know if it possible.