It took me quite a while to notice the gauge on the left side of the screen! I’d just been picking choices without really thinking about it. (That’s not a UI issue, by the way—I was just tired and completely missed it.)
That said, I’m still not entirely sure what exactly causes the gauge to change. Maybe I’m just not very observant, though.
I did feel that the presentation was a little simple in places, which was a bit of a shame. I think using a wider variety of sounds could help a lot. In particular, adding SE like footsteps would probably make the game feel a bit richer and more immersive.
It was a good game! I'm looking forward to your next work!