Well, there's way for improvements.
I can see the concept through the gameplay, it's something similar to a fighting game or a certain subgenre of close combat action game I think - there are many moves and a dash gauge that slowly recharges.
The gameplay itself though is what needs more investment in. Right now it's poor, what with the moves that feel a bit sluggish, and maybe some move-cancelling could be considered.
The boss fight isn't suited to the training you had to overcome against the DOOR. Marisa never lands nor stays still so you can't wombo combo on her. It's very difficult to rate the challenge she offers due to the state of the gameplay.
Though I've noticed this purple bar which I presume is supposed to be the Amulet gauge? But said purple bar drains at the same rate as Marisa's health so I think it won't do anything as is.
I gotta say though, this game is looking pretty, and I can tell there's a sense of detail in the background's art.
I featured this game in my showcase video - watch if you want to see Flan struggle against a door for three minutes:
https://youtu.be/PoWrHcmGjbU?t=6690