I finished the game!

It was pretty enjoyable, despite a few usability issues, like the lack of gamepad support and the textbox being difficult to read because the text moves during the typewritter animation (and pressing the button doesn't simply complete the animation, it directly jumps to the next textbox, so I missed quite a few instructions this way). 

The jump was also difficult to control as I would sometimes automatically roll off platforms. 1-tile large platforms were very difficult to jump on, even with the double jump.

The bat has a really short range, making it hard to fight the shadows. It got a bit better once I found the sword, but in the end I mostly avoided them. I really liked the slide though! The Metroid-style ceiling-climbing was nice as well.

The music is good, the graphics and animations get the job done. I liked how some shadow devils were sitting and balancing their legs, like children. It made the reveal from the second spider boss more impactful.

With more time to polish it, I can see it becoming a pretty nice game. Keep it up! ;)

Fun game! I loved the movement and the background music got stuck in my head