Fell into the void a few times. A player catcher to reset the player afterwords would help a lot to prevent needing to completely reload the game. One of the collectable rings was positioned a little too high that it couldn't be reached no matter how I jumped at it. And the final platform appears to not have a collision mesh applied so you fall right through it around the edges.
I think the player speed was a smidge fast with the lack of guardrails to prevent the player from falling, but overall, a good first go with Godot with the limited time we had to work on these projects.
I would spend a little more time considering your level layouts for future projects, there were spots aside from the path to the end point that could be explored, but it only took you farther from the goal and didn't provide a way to come back to the main path causing the player to have to backtrack to the start to them move towards the goal. And at the goal there's no way to backtrack into the level again so if it were a larger level and you needed to find specific things, you would end up being stuck and need to start over.