This story fell pretty flat. MC dude's parents didn't die because of the mountain gods, so there was no such traditional connection. The only connection was that since a mountain god was present when his parents died, he now wanted to die when one was present as well. I suppose it's not psychologically strange even if it had got absolutely nothing to do with the mountain gods. They were just something the MC couldn't help wonder about, believing he has nothing else in his life.
Funnily the only thing I really liked in this oneshot was the minor twist of the bully-looking guy badmouthing Kaname, saying there's nothing else going for Kaname but the whole "woe is me" attitude. At that point I indeed just thought he's a wannabe tough guy jealous of Kaname and he himself would deserved to get beaten (like he did). But then in the very next scene we got Kaname exhibiting that very attitude by basically blaming Senkawa for something as bizarre as keeping him alive while his whole family died, accusing her of only keeping him company out of pity, and all that. If that is not "woe is me" attitude, I don't know what is. So, the wannabe tough guy was actually speaking the truth!
Other than that, it's stupid to leave those things to hunters with their small calibre rifles. They probably needed to shoot at that thing a hundred times before it finally fell. That's prolonging its suffering a lot. Seeing how they still could take it down with small calibre firearms, it means the JSDF could have done it in seconds with an autocannon, or rocket, or other means available to armed forces. The beast wouldn't have needed to suffer unnecessarily.