While I have to agree this does feel limited to a tech demo, it also seems like the perfect foundation to build into a larger game. The visuals are nice and the left-click/right-click combo attacks are pretty interesting, there just needs to be somewhere more for it to go. Maybe with some meters or other mechanics to incentivize not spamming attacks as a suggestion.
Shoot the Bullet is one of my favorite main series games, so the concept of attacking danmaku is definitely something I would play if this was expanded on.