I'm going through Shiny Days right now, and it's even more of a technical disaster than School Days HQ. The first freeze happened within less than half a minute from starting, and it was just downhill from there.
After a ton of crashes and freezes, I began troubleshooting like a madman for hours on end. I tried a billion-or-so different fixes in Windows 10, like playing in Windowed mode, different compatibility modes, closing all other programs and so on, and then I gave up and figured I'd try playing it in Windows 7 instead. Problem was, I didn't have Windows 7 installed anywhere, and getting that taken care of turned out to be easier said than done.
I decided to install it on Boot Camp on my MacBook, but then I ran into all sorts of trouble with that instead. I had to pick up old Boot Camp files because the newer ones were incompatible with Windows 7 on my machine, and when I finally managed to install and get into the OS, no devices worked. No USB ports, no network, etc, so there was no way for me to install the game.
Defeated, I moved on to install Windows 7 on a USB drive so I could use it on my PC, but after a gazillion BSOD's and whatnot, I accepted that this apparently wouldn't work either, hung my head, sighed and turned to my last resort: An old computer I haven't used in forever.
I had to make some hardware changes first, but then I was finally able to install Windows 7 and start Shiny Days again... only to see it freeze within a couple of minutes. I gave it one final attempt by switching to Windowed mode, and apparently the combination of that + Windows 7 seems to have done the trick. ~2 hours and no crashes or freezes yet.
This has been a battle, let me tell you. I have never before fought this hard to make a visual novel or game run on my computer, and it feels kinda weird that it was for Shiny Days of all things. I guess I'll blame my OCD tendencies.