[iceflinger]

Splatoon 1 doesn't have dedicated servers, the matchmaking is done on a server but the game itself runs peer-to-peer

[debugnik]

You're right, my bad: a quick search lead me to think that it had some server dependency that had been shut down prematurely, before the console's own online services.

I'm guessing the matchmaking is part of the Wii U's shared online services and not game-specific.