It was quite a pleasant experience reading through this, not gonna lie. Let's go through the feedback:
Writing:
The introduction cutscene was actually a nice touch, showing the facet of the main character we will be playing the game through. It also goes into his personality of being a tired guy that just wants to play his game. The writing however is a bit off and does not reflect his personality well.
"I'm glad that I don't have work tommorow.. even though I have nothing to do"
and
"Even though I have no money to buy the latest game".
These are some examples of dialogue that does not feel realistic. It sounds like he only recently had the epiphany that he did not have enough money. Did he recently helped his friend out the night before that caused him to be in this situation? If not, why did he not have enough money so suddenly?
If he, infact, did not have enough money for a long time, maybe he would say something like
"Just 2 more days to go.."
Which implies a few things: (1) he's waiting for something. Which can understandably be his paycheck.
Or maybe he doesn't even say it, maybe you could show him looking at the calendar fill with crosses, which implies the same thing.
The main character and Number 7's relationship is good, that they can both bond through video games (and especially the same game at that). However, the writing and dialogue is too fast-paced during those sections. You should slow down a bit more before introducing number 8 and 9 (or was it 6?) and flesh out number 7's character. Add a bit more nuance to the writing. Maybe Number 7 raises his arms in excitement when they talk about the game? Maybe the main character is a bit more self-contained and wants to share his excitement and feels awkward to do so?
Number 8's character ( the main rival) motive is very clear cut and in my opinion, the most well explored in this story. He's a desperate family man and when the situation goes dire, he turns to this to save his family. However, the fact that he would be determined to kill another person so easily (near the ending) is a bit off-putting. It does not reflect reality well.
I think we need to explore number 8's character a lot more to justify his actions. Perhaps during the final game, the main character has to try talking into number 8 to get him to open up more. Why was he good at knife fighting? Did he have a criminal background? Did he already lose someone close to him before?
One of your biggest weaknesses in this visual novel is the lack of sensory details. What does the character feel, see and taste? When number 8 attacks the main character with a knife, maybe you can write something like
> You feel something hot trickle down your fist and you glance at something unusually familiar. It hits you a second later when it drips to the floor - red and flowing.
Ultimately, the story flows at a very 'monotonous pace'. It doesn't feel like there's downtime, and no escalating climax. The sudden outburst of lots of people dying in the beginning feels very off and is not a good way to build drama and climbing action when everyone dies in the beginning. You should make more and more people die slowly as the story progresses to introduce escalating action.
As for the moment-to-moment writing, slow it down when moments call for it. And include more sensory detail to enhance the moment.
Music:
Is pretty good! It has a weird, unusual rugged feeling to it the reflects the atmosphere at every part of the story. The only weirdest and off-putting part is perhaps in the introduction with a somewhat happy jingle to it.