iOS Basic - Multiplayer Options Available?

I'm having a stab at my first game (exclusive to the iPad) with the intent to use multiplayer features . At the moment I only have iOS Basic and after looking at the license differences I'm still quite confused about what options are open to me for playing multiplayer (preferably not simply LAN).

Could anyone break down what iOS Basic multiplayer/network options are possible on the iPad. Can I do 'deathmatch' style games, or am I limited to gamescores via gamecenter?

In my head I'm picturing someone clicking 'Multiplayer' - which matches them with a single opponent (or available servers?) and they have a battle (ie: Mortal Kombat/Street Fighter etc).

If this style is possible, what is the type of networking that I'm looking for? This week I'm going to be running through the Unity(& M2H) multiplayer tutorials - but if someone could point me in the right direction that would be great.

At the end of the day If it means creating a single player game until I can afford the Pro licence, I'll do it. But I really have a good few MP games I'd like to push forward.

Thanks in advance!