I played this game after enjoying Paradigm. It certainly felt believable, and I could understand Derek's thinking even if I didn't always agree. I'm not sure what the overall point was, though.
I got Bad End, having gained no friends, but I'm honestly not sure what choices I could have made to get a different outcome. I strongly suspect there was no "good" ending. I didn't reject Mia when she appeared, so I'm not sure if that could have changed things somehow. She seemed to only be a positive influence, though, so I doubt it would have made things better.
I started to suspect she wasn't real pretty early on, with the way Derek kept saying he had no friends despite her clearly being his friend. And classmates were so weirdly, blatantly avoiding and excluding Derek towards the end that I was waiting for an explanation, like they saw him talking to himself (imagining Mia) or something. Or maybe he had been bad to them in some interactions that we weren't shown. But no such explanation was ever given.
I felt just as baffled as Derek when people would strike up conversation one day, but then have no interest the next, or when they would see him and then immediately avoid him despite supposedly being on good terms. I suppose his negativity was supposed to be offputting, and his thoughts weren't always great, but in all the actual dialog the game had, Derek seemed perfectly reasonable and polite, so I'm not sure if this was a case of unreliable narrator or what.
When Mia started psychoanalysing Derek, I had hopes that she might convince him to seek actual therapy, which he seemed like he could clearly benefit from, but nothing really came of that either. I could understand a game like this where you'd be provided choices like seeking therapy or finding clubs with people who shared interests with Derek, that he could connect with better than with his classmates, but it seems like you're just forced to play through the experience of someone who never even considers such avenues to better his situation.
If the point of the game was that people like Derek should change their thinking, try other things, or seek therapy, it didn't really come across. It almost seemed like the point was more about the classmates, and that they should be more open to people like Derek when they try to connect, but as I mentioned, I'm really not sure why they weren't more open to begin with.