I don't get it, but every time you die, the song plays again.
I like the idea of the ennemies you have to deal with it are cards. I just wished that each of them had an unique attack pattern, like in Deltarune's Jevil fight.
Viewing post in the dice-card pile jam comments
In case you don't know, there is a Jevil attack that lauches squares with a different symbol.
The ♣ shoots 3 bullets at a time at you in a spreading manner.
The ♠ shoots 8 or 12 bullets in 8 or 12 directions, I forgot how many.
The ♥ shoots 4 bullets in 4 directions, then shortly after, they spin around an invisible point clockwise that moves towards you, so those bullets moves a bit towards you too.
The ♦ shoots multiple bullets directly at you, but the thing is that the first shot is the fastest, and the last is the slowest.
I think you can make something similar in a post-jam update.