I mean, as well written as it is, there's still a fair bit of stuff you need to gloss over. This alternate reality or whatever it is seems to operate pretty heavily on dream logic. Sometimes that's game mechanic stuff like random $20 bills strewn everywhere that replenish every morning, water bottles costing $100, or adventure game-style item combination puzzles. Sometimes it's stuff that's technically possible, but unlikely-to-unthinkable outside of porn, like the previously shy, insecure teacher also having a history of making erotic workout/BDSM tapes (admittedly some supernatural bullshit's involved with her) or the school nurse secretly being the head cheerleader's semi-willing sex slave. Sometimes it's stuff that only works in porn, like aphrodisiacs that instantly make the consumer uncontrollably horny with no side effects. And sometimes it's random stuff that wouldn't even make sense in porn, like a bonsai turning into a tentacle rape tree overnight because you sprayed it with soda or semi-sapient malicious beavers.I agree it's not 100% clear but I will say to this that he in fact can still be a complete pervert and all around pretty jerky and they still react not that horribly to it. A lot of those choices even just give them lust. Imo I'm sure his attitude does somewhat factor into his better social results as the relationships develop, but it does seem like his starting point there's already a strong change affecting everyone's general disposition.
Honestly, I just cannot fathom it being purely him. If that turns out to be true, that would be a rather cheesy cop out for a game this carefully written. That would mean not only did the game gloss over all the real character development that lead to his reform, it also would also be an unrealistic background for how he ended up that way. Young people are highly malleable and subject to peer pressure. If life was already beating him down that hard that early in life for something he can so easily change, it is almost certain he would have learned to adapt before adulthood. Even if he had to fake all his interactions with people to fit in. And if he is one of the few that just couldn't adapt, then it would be indicative of some kind of social disorder that prevents him from changing. And hence he could not so easily be reformed by a mere text message telling him to do better this time.
And are we to believe he was also acting like a dick to the janitor as he did to everyone else, but she liked him anyway? Or did he shit on everyone but the janitor? Both are implausible. Janitors are usually the most disrespected staff members by such students for their "dirty" job. And the common janitor-student friendship trope almost always involves the janitor taking an unfortunate social outcast type under their wing. Reason being janitors relate to being unfairly looked down on. It would not make writing sense for that type of character to look after a jerk that purely does it to himself.
Don't get me wrong, it's awesome, but there are some things that don't have total internal consistency no matter how you look at them. It makes me a little nervous that the dev might go for one of the classic cop-out "none of this was real" endings (dream/dying delusion, purgatory/divine test, or fourth wall break/it's a game all along). The writing's good enough that I'm hoping they can come up with something better, but I'm not sure how to stick the landing there. In the meantime, I'm just trying to come up with the most reasonable explanation that requires the least additional explanation.
It being him also explains why he continued to suck so badly after high school, rather than even making a token effort to make something of himself once out of the toxic environment. Don't get me wrong, I've dealt with depression, unemployment, and the ensuing doom spiral, I get the lack of motivation, but I draw the line at blaming everything in the world except yourself for it. Having gone through that kind of depression in my mid-20s, I also take issue with the idea he repeatedly seems to espouse (at least in the prologue) that his life was over and ruined at the ripe old age of 25. I get that it's not easy, and depression makes it way harder, but you have to start somewhere, and the real "Another Chance" is the next day.