You'll most likely love Nine Hours, Nine Persons, Nine Doors.
I've seen people making comparisons about both games when Corpse Party was released, but I haven't played 999 at that time yet. I played 999 throughout this week and just got to my first bad ending, and I gotta say, it's a horror game as thrilling and fulfilling as Corpse Party.
In both games, you're clearly dealing with the unknown, even though at first on the two games, you have a clue on what may happen through the game (like you, dying, and chances are, more than once). Corpse Party's focus on gameplay was finding the right rooms, the right items, running in time from the chasers and managing to find everybody.
On 999, the focus is on the puzzles, and what you're gonna do during and after them. There are less "choices" to make during the game than Corpse Party, that every corner may have Death waiting for you. The basic choices on 999 are the rooms you'll be entering, and with whom. Who's innocent, who's guilty, is everyone innocent, or is everybody guilty?
I guess 999 plays much like Book of Shadows, from a "first-person perspective" and you directly get in contact with the items and your exploration. Everything mentioned, they're not the same, neither alike, it's a matter of suggestion that's helpful these days where most "horror" games are action-oriented, and you don't really feel bad with your choices as you can just instantly continue after them. With these two games, every choice counts, either for your favor, or for worse...