For a jam, it's pretty good. I personally didn't enjoy the music because it was quite distracting from the game. I'd love to have some more clear sounds.
The enemies felt kind of unfair. When I lost, it felt like I lost to chance because everything was too fast and there was no skill involved. Maybe have enemies telegraph their attacks a little bit earlier by some kind of indication.
Maybe also have the screen zoomed out for the beginning and get closer over time to make it a little little little bit easier in the beginning?
Maybe I'm also just bad at games. It said Hard and Fast on the box and it delivered.