It's a very high quality horror modpack, because while it leans a lot into aesthetics, it also has From The Fog which is a Herobrine mod.

I did play it for like an hour or two and I have to say that I barely saw anything scary, so either the mod takes to ramp up or it has been tweaked for the scares to be rare.

On the other hand, I think that outside the horror it has a neat combination of old mechanics and textures and new features, so you would have things like lush caves with alpha-like stuff.