I deleted my comment due to two reasons:
1. It wasn't constructive feedback
2. The game updated since I played
Theme: Not exactly adhering to what I'd call horror, but themed around the subject of demons and horrific entities
Fun: Very linear experience with a story to tell. The player isn't given any wiggle room to fight enemies or make choices, and there is nothing to explore with. The game could benefit with some points of interests or pickups, maybe even something like life potions. A way to win the game without submitting to the demon, rewarding player ingenuity or planning, would make this a lot better
Game Design: The pixel art was really nice. The movement felt very sluggish and choppy, like the inputs were checked only once in a while. Allow for checking for input more frequently - when I pressed an arrow key, it didn't respond roughly half the time. Other than that, the story could be less linear and could have a secret (good) ending. Other than that, it was an okay, enjoyable experience