Wow, what a great game. The gameplay is really fun and the graphics style is oh so good ^_^. Great job!
I think there are a few things that could be improved:
- The dialogs on the beginning of some level are repeated when you restart, I think it would be better to only show them for the first time
- It is sometimes hard to tell if the bullet is going to hit a vampire, I think some kind of indication could be used in the vampires that the bullet is going hit
- Sometimes the mirrors seemed to not ricochet the bullet in a way the player could expect from the appearance (aiming in the edges of some mirrors), this might be because of the underlying detection mechanism differs from the pixelated sprite assets ¯\_(ツ)_/¯