I mean if we're trying to source where "liminal space" started, I'd like to add Portal and Portal 2 into the mix. It didn't have the surreal, creepy components because jump scare horror games like Five Nights hadn't been popularized yet but the entire second area of Portal 2 where you're introduced to Cave Johnson and the older Aperture Science HQ is very much "liminal".

If we want to go deeper, then I really think its Earthbound's absurdist take on childhood adventures with cultists, ghosts, dreamscapes, etc. but I think at that point I might as well say dice games influenced things.

I don't think it's too far to include Earthbound. After all,

  You cannot grasp the true form of Giygas' attack!