I think you haven't read the limitations on sound - it must be monophonic (only one sound can play at any time) - and while I don't think there are explicit limitations on what sounds you use, I think it's more authentic to use the sound pack and soundfont in the resources.
Regarding the gameplay, I'd definitely add an animation to attacking - at first I thought it was broken, but no, it just doesn't do anything unless you're standing right next to an enemy, which feels non-immersive. I appreciate the coyote time - it's rare to see in games like this - but I still think a rectangular hitbox would be better than a capsule; sometimes I'd slide off the edge of a platform. I'd almost never recommend making textboxes disappear based on a timer, rather than disappearing when the player presses a button; different people have different reading speeds, and it's easiest just to put them in control of the dialogue speed (for most of them, I was waiting for the text to disappear, but one was so long that I didn't manage to read everything!)
Finally, while the story bits were intriguing, the gameplay was repetitive enough that I didn't feel like finishing the game - I'd recommend adding more variation in the level (some interesting environment elements, like skulls, bodies lying around, etc. as well as random events, such as hands rising out of the ground with a sound stinger, which I feel could add to the atmosphere of your game), more variation in the gameplay (ghosts requiring different tactics to defeat, e.g. moving around, rotating their line of sight) and possibly a map to help you locate the last ghosts when you've defeated most of them.