Hahaha, I think I know what you mean when you say "secret". By the way I've tried the game in Windows 10 with the exact same settings, and I've noticed a significant difference with the bird's flight. My main computer is Archlinux and here the flight is far more seamless, smooth, while on Windoze it's kinda edgy. I just thought you should know. By the way I'm excited with your upcoming "big re-release".
¡Felicitaciones! #SamuraiPunk :)