I'm not sure what I think about the usage of the theme. The theme is bidirectional and that basically only applies because you can either press left or right arrow, but it would be nicer if you could use all the arrow keys. And your movement is quadra-directional (as in, you can move in 4 directions). Maybe there's something I'm missing here.
Many hitboxes were quite big. It's not a big problem with the end trigger, but the death trigger killed me even through walls.
As for the music, I don't really think that there is any time in the 3 hours to make music on your own. Typically when you see people make music for this jam, it's done by a seperate person who either only does the music, or music and sound effects. That's because with such a short experience it's better to focus on mechanics rather than on the sound design. Your theme has some nice melodies, but without the harmony (as in the chords) it feels a bit empty.
It was still a nice experience. Good job and good luck in your Godot journey!