Nice job on this -- I played this to the ghost boss. I liked the mix of palettes in different levels here, and among your creations I liked the black walking enemies especially. The level transitions and music are great, and the opening image gave me 1930s animation vibes. The difficulty ramped up in a nice way, too, though it was tough love to have to replay all three levels to get a few lives against the difficult boss. Classic games were sometimes like that, though! I also liked how you created a story around your gameplay without it being too intrusive. The several UI elements work well, too.
Some hopefully helpful feedback: (1). I would try to make your pixel sizes uniform. It looks like perhaps you resized some of your sprites and other art such that the pixels are a variety of different sizes on a single screen. Some players find that this creates a hodge-podgy look, even where the art is otherwise great. (2). My whole first level was just blackness with trees and characters (image below); it looks from your dev log that this was meant to be a forest scene. Similarly, at the end of level three, the whole screen becomes black at the end and I just had to jump and attack to get to the end (image below). I'm on Firefox on a Mac. (3) When the player lands, she appears to go through the ground and then reappear back up on the ground. Perhaps your collision detection parameters need to be adjusted?
Nice job!