Impressive job for a single day! Specially since you included sounds, filters, transitions from one day to the other, etc., everything around the actual gameplay.
You mention the game to be really hard, but once you find out the best strategy is to boost as soon as you start getting shot, it becomes rather easy (a bit repetitive). This is sad because there clearly are some mechanics to attack enemies, though they're pretty much suicidal.
Nonetheless, congrats!