Wonderful atmosphere, with escalating tension, at least at the start. It achieves a lot with relatively little, which is impressive. Thumbs up.

There were a few tech irritations for me, that interfered with immersion. WASD for movement, no arrows options (I hate WASD). I pressed Escape to pause and it quit the game with no warning. When the game ends it seems to crash to desktop, so at first I was going to delete it. And on each load there's a pause and I seem to have to right click before it enables movement. So they did weaken the (excellent) atmosphere a bit.