I like the idea and concept, first time I play a bullethell in 3D, nice! The dialogues are very well embedded, they give it depth.
But there are things I would change to improve the gameplay and overall feeling. The bullets are almost no different from the energy balls, I would make the game more frenetic (gameplay, music, difficulty, etc.) since it is a bullethell, it's a bit difficult to calculate how much energy you have left, the annoying enemy firing sound, more shooting patterns... I know there's not enough time for almost anything in just a few days, but I'd love to play a game with those improvements!
Overall I think it's a very good game to be your first entry in a game jam, and the atmosphere is great! Good job