I tried to fix the vertical speed but I have no idea how to do that in the Gdevelop Physics Engine without also affecting the "walking" speed. I could in theory add 4 extra points to the object for 4 independent ground checks based on the orientation of the gravity and add a second set of controls for the object in the air. I'm not sure that the physics engine would handle that well and it might cause more bugs than it would add features. I was also limited by an extra day as I was busy the last full day and a half of the jam. I might keep playing with this idea as a side project though. Thanks for playing the game. I appreciate the feedback!