I spent a while reducing the game's bandwidth footprint as much as I could; I have a writeup on my site about how the game works if you're curious[1].
That said - there is only a single server here (Anycast shenanigans were out of scope), so latency does get worse the further you are from the server (NYC). I think the game is pretty playable for a surprising number of people, but you'll definitely struggle to play from, say, Australia.
Fun fact: two sub-problems that I encountered while thinking about this game made their way to HN's front-page - TCP_NODELAY[2] and SSH keystroke obfuscation[3].
[1] https://eieio.games/blog/secure-massively-multiplayer-snake/
[2] https://news.ycombinator.com/item?id=46359120
[3] https://news.ycombinator.com/item?id=46723990