THIS has the soul 100%. i'm reminded that a simple but compelling concept is all ya need, this speaks volumes to that. As for feedback, An audio cue for damage would be helpful. Other than that i actually enjoy the difficulty quite a bit, older games were unforgiving and this is almost in the same vein. This in my opinion, makes it fun, because its not impossible. It feels like it's a skill you can learn.
As for bugs, as the apparitions get super close to the screen their hit boxes don't seem to line up with the actual entity, its around 2-3 pixels inside the outline. this might be because its looking for the entire crosshair being inside the outline, i am unsure.
Whenever you make it available for download, ill be the first in line. id love to play this on my own time. Bravo!
And congratulations on your first game!