Is this kind of game fun if I only play single player? Or is this only worth it if you want to get into the multiplayer?
I enjoyed single player but multiplayer is definitely more interesting due to the greater variety of plays humans will make, AI isn't too shabby though, but I can only really speak for myself.
I've been playing single player since last night, total of about 3 hours - having a blast, and I have barely scratched the surface. But then again, I was in love before the tutorial wrapped up. Can't wait to get better and experience some epic multiplayer action. What's even better is knowing that part 2 (El Allemain) is in the works already.
The Shenandoah Studio forum has a topic devoted to sharing Game Center IDs: http://www.shenandoah-studio.com/Forum/viewtopic.php?f=7&t=3