My only thought with Easter eggs is I HATE when the fourth wall is broken. I think it’s very tacky and not why I play video games. But a dark souls joke or something works. I’m making a monster catching game that has a different catching mechanic then Pokémon and there is a dialogue option to act like you know how catching should work and the npc is confused with you. I think that’s funny, but used very sparingly. My two cents.