ReynardFox: Isn't it nice to know that GOG rejects highly praised shooters for being too niche, while having no problem selling a pigeon themed dating sim.
No bias there, nope, none at all.
I'll defend the game, and then why it's probably here:
1) Hatoful Boyfriend is actually good and worth being here on its own merits. It's a remarkably clever game that hides a lot under its ridiculous theme, and has one hell of a mid-story twist.
2) It's published by Devolver Digital, who have a long-established relationship with GOG and access to enough titles GOG clearly wants that they can throw their weight around a little. GOG's not about to piss off the company that holds the keys to Talos Principle, Hotline Miami, Shadow Warrior and a few dozen other hot indie titles, so they'll roll over and let Devolver have its fun with wacky imports now and then to keep the marriage happy.
Basically, Devolver could easily get Mushihimesama on GOG, and Degica probably couldn't have gotten Hatoful on GOG.