This... This is, without a doubt, intentionally creepy. And the subtext is borderline horrifying. I am unsure of how to remove it from a pool. It does not belong in "creepy for no good reason."
even though Koishi closed off her eye, rather violenty (it seems), she still sees herself in the same way. Only now she is much more isolated
Although that's depressing, it's not really frightening...
Funny thing, like 2 minutes after I made my most recent comment yesterday, I somehow became terrified of looking at my own reflection and seeing something demonic instead.
I think I see where I went wrong there. Her bangs in the foreground overlaid in her reflection's face and made it look like a creepy smile. On closer inspection, the foreground hair obscures the reflection's mouth and leaves us unable to see her mouth's expression.
Similarly, the reflection's third eye and regular eye are both dripping fluid - thanks to the misinterpreted "smile" and dark colors of the reflection, I'd further misinterpreted that fluid as blood, when it's just as plausible to be tears.
