Holy moly, this was awesome! The size of the dev team was absolutely put to good use :)
I would absolutely pay for and play the full version of this sometime, especially so that I could try some more challenging levels. As a Level 1, the current difficulty of the game makes sense- though for a jam release, it could probably have been tuned up a fair bit. Zero criticism about the game being short though, I understand that's just a jam time limit thing- what's there now is fantastic!
The UI and art was great, I loved the portrait artwork in the dialogue parts as well, and the 3D perspective after beating the boss was awesome (I couldn't tell if that was being rendered or was just an artwork, but I really liked it either way)! I did notice that the score screen at the end of the level was filled quite slowly for how many "Enemy destroyed" entries there were, but given it's the end of the game for now that's a pretty insignificant issue to have.
The whole game reminded me a lot of Picayune Dreams, but the shield/wave mechanic was definitely its own thing and a really cool interpretation of the jam theme. The music was very reminiscent of that game as well, in a really good way! I actually dug through your repo to find the music so I could listen to it again lol
Overall loved it :))) Would love to keep track of this game if it keeps growing. As everyone else has said, super polished, extremely impressive for a jam like this- I wish it had more eyes on it, but the curse of the downloadable entry is eternal and infuriating :(