Thanks for playing! I am glad you enjoyed the game and thought it was both fun and challenging!
Personally, I haven’t played Just Shapes & Beats but I have seen gameplay videos and was a little inspired I guess hahaha.
And yep, I think this game idea could definitely be expanded with more enemy types and songs. Different enemies can have different behaviors (One can lock on to a player, but not mirror alike the game) and also different projectiles (Homing? Accelerating?) that could represent more sounds in the music better!
An idea that I had was different themes w/ different art styles for the enemies, projectiles, backgrounds, and players depending on the song genre like Muse Dash does.
To address shooting, I was planning on having a little rhythm input game within the bullet hell game itself so that the player could shoot homing projectiles to the beat as well, maybe with enemy & player turns, but this turned out to be too much scope for the jam and the time I had, so I had to cut my game ideas.