Hmm, that's a really tricky question to answer! Maybe someone else can pipe in?
I feel that it does. The game clearly draws on twin-stick shooter design, and having one 'bullet' on screen at a time is atypical.
I guess you COULD argue that your bullet doesn't behave entirely like a bullet (it stops where you shot it to, as opposed to continuing to travel), which may weaken the theme. That's pretty nitpicky though.
I rated it high on adherence, you'd probably need to find someone who disagrees and ask them why?