Thanks for the feedback. I think one of our misstake was to make to many levels. We have some ennemis that come later (in total if I remember well we have 12 different ennemi types with very different patterns including a boss). I'm not sure I understand your recommendation though. The background effect was made by our shader artist and sound designer during the jam.
Viewing post in Chaos in the Milky Way jam comments
It's true that the ennemis that fire bullets don't have different behaviours we could work on that. I'm a bit sad the other types of ennemis come so late because I think they have more fun patterns that perhaps would feel more fair. We have one that behaves like the dvd logo and bounces on the edges of the screen firing some bullets and leaving a trail. We have one that teleports every few seconds and fires a missile on the player frequently that explodes and releases bullets. We also have one that doesn't shoot bullets but gives a preview then moves quickly towards the player (inspered by sans lasers from undertale).