Great world-building, atmosphere, art, and voice acting. As others have said, it feels like an episode of The Twilight Zone (at least, the second ‘half’ does).
The game is also an impressive length for a game jam entry. It took me over an hour. However, the pacing felt a little off to me. The prologue/intro took me longer than the part in which the actual story is told, as it contained all the puzzles.
Although I very much enjoyed the game overall, there was also too much pixel hunting for my liking (even the hotspot indicators could be hard to spot, and I tried to avoid them at first, as the README file said they could spoil puzzles). At one point, I thought I had encountered a bug, but it turns out the puzzle had just been designed in a way that I felt was unfair. It had to do with hotspots, but I won’t say any more, to avoid spoilers.
That said, I know your main aim was to test PowerQuest, to see if you could make something polished with it. In that respect (as well as the others I mentioned up top), this was a resounding success. Great job. I look forward to seeing more from you :)