The sprites and background are done well, overall, the art is great! It's also good to see that a lore is incorporated within the game, notably, it follows the given theme.
As for the gameplay, it is nice to have many platforms to use when reaching and defeating the enemies, but I find it really dark and most of them does not stand out as platforms. Perhaps an outline might help on making the platforms much visible, so that the player can anticipate where and when to land.
I believe that the game delivered its executions based from its lore very well, and it can do more.