If a Dear Passengers demo is released, use the official Steam page first. Steam is the confirmed PC platform, and it is the safest checked place to see whether a playable build is public, limited to a Playtest, or tied to a temporary event.
Do not download a Dear Passengers demo installer from a mirror site, file host, APK catalog, mod page, or social-media reply. Those pages can rank for demo searches before the real game is available, but they are not official distribution channels. A real demo should be easy to trace back to Steam or FLEXUS.
This is especially important before launch. When a game is unreleased, fake installers can use the demand for early access as bait. If the page asks for an APK, a password, a survey, a browser extension, or a separate launcher that is not Steam, treat it as unsafe.