That’s pretty much it, especially in regards to turn-based games. Also, “cross-platform” is rather subjective. It could just mean two platforms, which is what you mean. But it could also mean more than one. There are a lot of cross-platform games, but not really a lot of turn-based ones. Really, Chess.com is the only one I can think of, but you already said you played chess with your friend, so that doesn't really help you out. I’m sorry I can’t be more helpful. And yeah, I realize this thread is from 2014. Well, I noticed that a while after I started typing this reply.
