I'm a bit of a wimp when it comes to horror games, so take this with a grain of salt, but I felt like this game had just the right combination of tense atmosphere and genuinely terrifying visuals to create a scary experience. Despite being a 2D pixel art game, the developer was able to still create that atmosphere, which I think is really impressive.
It's a short and... well, "sweet" isn't really the right word for a horror game, but I think you get the idea. Despite being a short game, there's a lot of variety in the scares so that no two playthroughs are 100% alike, and I'm sure there are many spooky things I missed throughout the three times I played.
If you're looking for something spooky that isn't too long, I'd recommend this game!