This was simple but clean and fun to play! It would have been even more fun if the challenge started to evolve - maybe different speeds or multiple hits to take down the enemies.
You can cheese the game by spamming LEFT,SPACE,LEFT,SPACE… repeatedly. Played in the spirit of the game though it was fun to interact with, I think you could enforce that spirit by having there be a cooldown for shooting, so that the player can’t just spam it.
I think you could say you applied the theme, in that you cycle around your aim. But maybe that would be more accurate if you could only go one direction.