Well-made game teaser, with qualities I love. Definitely not a 5-minute preview, it's a well-made, playable introduction with plenty of gameplay. Mechanics are very good, puzzles aren't obtuse or moon-logic, scenery/artwork/textures/lighting are above average, and it's got a delightfully creepy vibe without gratuitous jump-scares or needless gore.

Since initial publication, dev has announced full-on aspirations to expand it to a full game, and I'll be eagerly awaiting the finished result.

EDIT to add: Dev has expanded the initial Prologue to include more. It goes a step or two further in pressing all the right buttons for me, providing so much of what I love about creepy and mysterious environments. If you liked Shivers, The 7th Guest/The 11th Hour/The 13th Doll, Darkfall series, Gabriel Knight, Contemp(all of which can be had from GOG or Itch.io), or any number of similar titles, this'll be right up your alley.

Show the Dev some support when the Kickstarter goes live, and let him bring his vision of the long-abandoned cult's history to life. Who were they? Why did they leave this place? Where did they go? Perhaps more importantly, are they still around, and are they a threat?