Never mind. I appreciate all guesses

I have again played around with bundling the game plus Wine. It looks good. One single .app that can safely reside in MacOS' app folder. It's as fast as on Windows, everything works very good (okay, that's because its a simple 2D game which is handled well by Wine).

However, its size is around 420 MB, and from this, the game is only 200 MB. I'll see if I can host this somewhere.