Congrats on making your first game. It's not bad for a first project, and simply submitting something in a game jam is an accomplishment in it's own right. It was fun to play with for a minute, though I couldn't seem to get past the third jump. I will say, the rat was cute and the assets used for the terrain and background look great.
Here's some suggestions for what I personally would change. Put the rat about a third of the way in from the edge of the screen, instead of all the way over. Give the player a few seconds to get a feel for the controls before throwing obstacles at them. Explain the controls in either in the game itself or the itch.io page. Switching out the default Godot panel and button styles for some customized ones would help give it a more polished feel.