Mechanics-wise, I think it's pretty cool to have the player slow down when reloading. It made me pay more attention to when I am doing it. Having different enemy hold different weapons is also really neat. The use of a story board for the intro is a great addition.
The levels are too difficult for me since the player dies after at most 2 hits. I was not able to go pass stage 2. I felt that the controls can also be streamlined. Most of my death happens when I am reloading, and it feels a bit clunky to have to press another button ('q') to cancel the reload. Personally, I would remove 'q' and just make the player stop reloading when 'r' is pressed while reloading. You can also make the player stop reloading immediately when the shoot button is pressed.
Overall, I think it is a good start. Great job on the jam and good luck on your future projects!