It's a neat little concept and a cool use of the theme. However, I do think the following would make it a MUCH more fun experience:
- Make the bullets bigger! Like, player size at least.
- Make everything move more quickly - 2x speed at least, but experiment with higher speeds
- Hold-to-fire would feel better, especially if you add more enemies
- Lower enemy HP! Higher enemy count!
- More feedback when bullets hit something. Make the enemies flash, add more sound effects, etc
- The audio needs some work, really, I muted it after a little while because it was quite harsh and repetitive.
If you try that, let me know - I'd love to play again with those bits implemented 😁 The idea is solid, and while the movement takes a bit of getting used to it is really interesting and could be quite fun. I also love the amount of pickups!