I liked it!
Maybe a much larger rage meter, with a cooldown? so a means of encouraging the player to be more strategic with when and how much they are shooting.
And a more chaotic rage state could be fun - I was relatively quickly able to figure out the reversed controls and get comfortable with them.
Third things would just to be potentially having more dynamic enemies, or enemies that are better able to aim at you - I was able to find pockets where the enemies couldn't shoot me from a particular angle, and just sit and spam bullets.
But overall pretty cool, this is the first time I've played games made in the GMTK game jam and this is my favorite so far!