There used to be a feature where you could play with Game Center friends. Is that still possible?
No, Dave removed it when Apple went through a prolonged period of breaking it at regular intervals, because the game wasn’t being updated enough to keep up, and he was busy with Sapiens.
You can still play with your friends if they’re on the same network as you though.
There are some alternative methods…
Yeah, like PARSEC
there’s some others as well.