(Playing using the translation restoration patch.)
This is the first Visual Novel I've ever played! When looking past the odd pacing and (to my knowledge) unusual formatting of the divulging of information to the player over the course of each ending (of which i believe all are strictly necessary to complete in order to get the full experience), this is one of the most strikingly detailed, painfully unrelenting things I have ever played. I consider myself decently hardened to suffering and disturbing content, both in the real world and the world of fictional works, but this is an absolutely crushing experience, filled completely with content worth your time. It takes great care to display things in a complex, complete, if slow-burning way that I do not regret experiencing at all.

I've still not finished the "true ending" as I understand it to be, I'm still going through the side routes. But I had to stop after Kozue's Route to write this review because it genuinely left me stunned staring at my screen as the credits rolled.

Kozupi

The first playthrough is abysmal especially cause the main character is annoying af.
If you manage to get through it and play the other routes it's not so bad though, Game is pretty well written for what it is actually.

Chances are, if you're thinking of buying Chaos;Head, you probably played some other SciADV visual novel, likely Steins;Gate (or you watched the anime, I guess lmao). In that case, you should definitively buy Chaos;Head. It's a very engaging thriller/mistery visual novel that kept me guessing what would happen next at all times. It's also one of the best entries to the SciADV franchise.
The story is excellent, translation is good, characters and their respective routes are very well crafted, has one of the best (and most relatable, lmao) MCs from visual novels, and it's overall of very high quality.
I absolutely cannot recommend this enough. I would personally wait for a sale, but it is worth the price imo.