Multiplayer horror games, as a whole, is something that is rarely done correctly, because a lot of developers always fall short on either the horror or the multiplayer aspect of it. Some games like Phasmophobia are decent, but they have a weirdly steep learning curve if you ever want to play the harder difficulties; And let's face it, Phasmophobia isn't exactly the pinnacle of polish. The Outlast trials succeeds where a lot of other games don't:

-Actually a horror game (games like Hunt:Showdown and DBD are not horror games fight me)
-Fun with friends, and you can play with randoms if you are alone, (the co-op is optional but still actually integral to the game).
-The monsters have personality.
-While the game becomes less scary over time, you stay for how fun the game is.
-Uses the lore of the other outlast games well.
-Good difficulty ramping, (I still haven't beat the hardest stuff in the game)

I think this game is phenomenal for still being in early access (at the time of writing this), and I think the only thing they really need to add is some more maps and enemy types.