Wow, ok. So I had recently finished Kajitsu and planned to post my thoughts about it here, then promptly forgot about it until I saw this topic again. Without further ado: my thoughts from my vague recollections of a VN that at this point I had finished a few months ago.
Grisaia is more or less the VN manifestation of trying too hard. Completely absurd situations are presented and played straight not for the purpose of comedy, but are instead actually meant to be taken seriously. The entirety of Sachi's route is bordering dangerously close on some of the most ridiculous material I've ever had the displeasure of reading, and it did not especially help that the first quarter or half of the route was marginally decent by virtue of nearly 1:1ing Kotomi's route setup from Clannad.
Sachi's route is probably the most extreme example, but almost every route requires such an insanely high suspension of disbelief at some point or another that I could only contain my laughter because it was mixed with the horror that it wasn't meant to be comedic.
Mixing with all that is the fact that I struggled with finding reasons to like any of the characters. Yuuji is laughably overpowered and the fact that a good half of his narration was him figuratively sucking himself off only added to how frustrating it was reading through his shitty Gary Stu moments. Michiru was far too dumb and annoying for me to care about her fake behavior, and this was not aided by the incredibly long common route that somehow managed to precisely avoid ever diving even somewhat in depth to any of the characters surface personalities to make them more interesting. Yumiko somehow managed to become a useless vulnerable girl in the matter of a few hours of reading despite opening the VN as a crazy bitch that attacks people with a box cutter. Sachi was tolerable in the common route, but unfortunately her route completely blows any positive feelings I had about her character to smithereens. Amane was actually the most tolerable for me and her route doesn't do anything in particular to shatter her character despite diving into much of the same absurdities as the other routes, so I guess she's my favorite by those virtues alone. Makina was largely there for potty humor in the common and not much else, and eventually her mannerisms became so grating that I would just wish she would stop talking.
So the story was completely ridiculous and I didn't explicitly like any of the characters. What good there is simply gets drowned out in things like blowing up a school to solve your emotional problems (lol) and then fucking your boyfriend outside the school you just blew up immediately after (lmao) , and then there's the worst part:
Most of this shit gets retconned in the sequels anyway. There was almost no point to reading any of it.