I really like this a lot! the cute-pixel-gothic aesthetic is something i really love, the character designs are adorable, the chiptune music is fantastic, (10/10 would buy soundtrack), the clever use of fourth wall breaks feels Undertale inspired (which I enjoy a lot) and the story concept is interesting and makes me want to know more. i also enjoy the space jumping mechanic, it's fun and satisfying to just kind of jump around all over the place. i think a mark of a good game is if it's satisfying just to move around. I can't wait to see where this game goes!
one thing i would suggest is maybe instead of throwing the player right into a small boss battle as soon as they get the sword, maybe allow a small space for them to get used to the fighting controls, since i found them slightly difficult to get used to. or maybe the boss battle could just be tweaked slightly to allow for learning, like maybe having the boss slow down, have a smaller range of attack, or deal less damage. doesn't necessarily have to be all of those at once, even just the less damage thing could give the player a lot more room for error. on the other hand it's possible i just suck at keyboard controls, lol (i eventually did beat it after going back and playing a lot of swordball to teach myself the controls)
also, this isn't part of my review, but i can't seem to figure out what to do after said boss fight... the blob creature in the secret passageway says there's a key "in the last room" but i can't figure out where. the blob creature in the room just outside the secret passageway just tells me to look for a secret passageway, so i end up going in circles... i thought maybe the solution has something to do with the fact that August can blow out the candles in the boss room, like maybe there was some special way i had to blow them out in order to reveal something. but i can't for the life of me figure out what kind of pattern there would be to that, so i doubt that's the solution. a small hint would be appreciated, if possible...