I actually do enjoy the latter two SH games, and even 3 a lot more than 2 because it feels like a combination of 1's horror design with 2's campiness.
But yeah, 1 is just unique in the pantheon of jRPGs in that it's straight up horror throughout the whole game, from the enemy designs to locales you visit. The artistic vision and overall design is fantastic, and only slightly marred by unimpressive graphics (though, really, the animation work done for in-game cutscenes is actually really fluid, something carried over from its predecessor, Koudelka). The music, likewise, is very evocative of the places you visit, something that Covenant and From the New World don't hit the mark on often.
When I was a little kid, it was this track:
That sold me.
