Great game! Ill be rating it highly. Constructive criticism time! : Brutally difficult at first, but if you stick with it for a little you'll get the hang of it (I also didn't realize you could kill enemies for a little bit my bad :P), you might want to consider easing the player in just a little bit. I feel like the hitbox for killing enemies is a little small. Bullets going through platforms felt a little off to me, and I couldn't find a pause menu. Like you said the theme implementation isn't the best, but you get a free pass cause of all the confusion at the beginning of the jam.
I really liked the art and stylistic choices made here, and the controls felt very responsive. I REALLY liked the second chance slow motion mechanic, good job on that. Overall amazing entry.