You chose the word horror. Then in your examples provided wounds that were minor not horrible. It's unreasonable for you to base your counter argument on such reframing.
I must point out that a blast of glass shards to the head is likely to blind and do eye damage. If nothing else she'd be scarred. No plastic surgeons around to remove the scars. Forget about the technical work required to produce a scarred Naomi. Do you really think that would improve the story or that fans of the story want that?
Defenders control where they engage the intruder. Hana's already blown one away. She wasn't "in a rush". She moved in a controlled way. Popped out and shot the second one long before ANYONE was in a position to engage her. You're arguing for the defenders to behave stupidly (as the MC did in his attempt to finish clearing the house) and put themselves at greater risk, just to increase tension in the story. I submit that stupid behavior reduces tension.
That said I agree that the fight with the last intruder would have left the MC in pretty rough shape. Realistically he'd be pretty much out of commission for days.
My point is that, for many (probably the majority of) readers, the scene you desired would not have had an overall positive result for the story.
Hell I consider it absurd that there wasn't a comprehensive defense plan made well in advance and practiced to the point that, when the truck hit the gate, everyone immediately reacted to form a unified organized defense. Of course had that happened the intruders would have been slaughtered without having any chance to put the defenders at significant risk. Which would have produced a story that many would have found boring.
In the end the author told the tale he wished.
Anyway we each have our opinion. Yours is as valid as mine. We disagree, but that's fine too.
I'm not trying to insult you, but I think you're not understanding the meaning of the word horror.
I use it because the game, as the tag "horror" suggests, was meant to be a horror or at least contain some of it.
My examples were written, without too much of thinking about them if may I add, how such horror could be achived with plausible explanation in certain scenes without grave consequeces afterwards, not to horribly wound main cast. After all we want a happy ending, right?
As for Naomi example, yes you right, glass shards can be pretty dangerous and cause some serious injuries. Yet I do have to argue, or rather explain in greater detail, about why Naomi would end up fine and not scarred and in need of plastic surgery as you wrote.
Basically, she would be showered in tempered glass. Thousands of pieces of small shards not having enough mass nor enough room to gain enough speed to cause her more than a minior cuts. Yes, some of them could get into her eyes, yet it's pretty small chance, especially if she would, naturally, duck with head down, covering her head with hands. Although doing it while being showered could increase chances of getting one of those into her eyes, but still she would end up fine.
Now I have a little problem with understanding why are you explaining to me what happened in the game and how Hana acted in the game. I played the game, I know what happened. If this is somewhat argument to how Hana could act in my example, then all I can do is to ask you to not mix what happened in the game with what could happen in my example. In my example Hana rushed because she was angry.
Also I really do not like when people are putting words in my mouth, so please quote me where I wrote about " defenders to behave stupidly" or refrain from putting words in my mouth.
And to answer your question, yes I do think it would improve the story, because it would cause some horror which game should contain if it wants to be consider a horror and such thing would impact, as you also noticed, the perfect defense made without preperations. Story don't have to be logical, author can bend the reality to his will as he pleases, but the story should be plausible. Especially when people won't like it. What fans wants is irrelevant.