Level 3 seems to be stuck in an infinite loop where there's a trio of enemies. One central before 2 purple to each side of the original.
When the player perishes, the shadow remains. I like the game enough, there just needs to be more to it. Like something to collect. Different weapon. Each level has a different weapon array, but that's not changing anything during the level.
That boss in the second level, you need to space out the sounds, because it builds louder and louder. Faster projectiles may also help, since the player can travel the same speed.