OHMYGODJCABOMB: The title says it all. AKIBA'S TRIP: Undead And Undressed on GOG is nothing more than the so-called "Steam-rip".
The game has Steam files in its installation folder ("steam_app.dll" and "steam_appid.txt") and it interacts with Steam!
Luckily, I also have this game on Steam, but I think users who don't have this game on Steam might have problems as Steam starts tracking stats for this game. It can be perceived as an attempt to launch a pirated game and lead to the banning of your Steam account.
Maybe you should remove this game from sale until you fix this issue?
It might be a dummy file. A LOT of the GOG games with Steam files just have dummy files with redirects so that they don't actually call Steam. It circumvents the Steam API rather than uses it. I don't know if that is the case for this particular game.