Very nice aesthetically.
The music felt a bit weird to me. It was eerie like the theme suggests but at the same time it seems too calm/repetitive for the shooting. Also shooting/explosions sound would be really cool!
The gameplay felt a bit complicated using a keyboard. I wish aiming with the mouse was available. Also, I didn't know when was I dying, a health bar is very needed. The enemy bullets could be faster too, I killed one of the initial enemies then approached their weird projectile things, until I understood those were the bullets.
Also, a scoring system would be neat!
I liked the idea overall, it feels maybe too ambitious for such a short jam, but I don't know. Still, it is mostly functional, congratulations!