The bullet hell combat of this game kept me entertained for quite a bit. Made me feel determined to beat it! Overall it's an experience that kept my attention and I did enjoy. There are some things worth tweaking to better improve the experience.
Here are my suggestions:
The main character standing up straight stiff is a bit strange. His hitbox can seem excessively large during moments where there are a lot of shots on the screen. Even just having him crouch or bending his knee in a stability stance would help with both those issues. Some minor movement animations on the main character would be a nice detail to make things not feel so static. I'm also curious as to why he is throwing knives when the picture shows a staff. Wouldn't it make sense for him to be shooting ink from his staff given the game title?
A short intro explaining the main character and his reasons would be a nice touch.
The lives section should just show lives left instead of a counter of how many lives you once had. Leaving the original number up there makes it seem like you can earn those lives back. In regards to the screen layout I would suggest making the overlay not part of the playable area. Enemies or the character hiding behind the UI elements was a bit jarring at times.
The vertical font on the scrolls make things difficult to read at times. I understand it's a style choice since that is how Chinese classical characters are written. But the death screen in particular was straining on my eyes to read.
Programing was done well and I didn't experience any errors. The sound also not stepping over each other during enemies shooting was pleasant.
The music was well done and had the perfect mixture of wonder with enough fast paced movement to match the visuals. Maybe adding something more dramatic for the boss fight would enhance it but no issues otherwise.
Keep up the good work and I can easily see things getting better! All the core stuff is there and most importantly it was fun to play.