Not sure what OS you are running, but if you are using Linux or a Steamdeck, go to compatibility and try setting it to proton 7 or 8 (mine is set to Proton 7.0-6). It's what worked for me as I had the same problem. I can't help you if you are using WIndows, I have no experience with running this game on Windows. Hopefully someone can give you a fix if that doesn't work.

I'm getting the same issue on Windows 11. I can run the VN perfectly fine through "unofficial means", so it's something to do with Steam.

Check if there is something in one of the log files. You can find them in your steaminstall directory /logs. I don't know which one to check, but I recently fixed something in an other game by checking some of these. Open the game and after crash, try to check in a couple of these logs (console_log.txt, appinfo_log.txt, content_log.txt, ...) if there is something about Little Busters in there, eg a file it can't find.

I will try to remember to install the game on a Windows machine in a couple of hours after work to try to see if it works for me (although mine is Win 10) and if I can figure out in which errorlog the errors should be.

Recently one of the games stopped working on Linux because it couldn't find a .so file (which is like a .dll in Windows), apparently the dev mistakenly removed it with an update. I fixed it by copying the file from an other game. it might be something similar here.

I manage to solve the issue but it's extremely specific to my computer so I can't really share the details . Nothing to do with Little Busters.

I'm having the same issue. Win 11; game window doesn't even open.