For the most current "fixed" versions and detailed developer notes, you can check the following sources: Ci-en (Developer Blog)

— Fans of the dark fantasy horror visual novel Syahata’s Bad Day can finally breathe a sigh of relief. After weeks of player complaints regarding game-breaking bugs, save corruption, and progression blocks, the developer has released a patch that appears to fix the most critical issues.

However, if you recently purchased or downloaded the game from DLSite, you might have run into some frustrating technical hiccups. Many players have reported issues ranging from "black screen" crashes to translation errors or controls not responding.