Since I'm planning on having a database to store data, it will be easier to allow users to create multiple user profiles, and one device can then be used for multiple players. (Even using one login on devices that allow multiple device users.)
So I created a mock up of what I expect the user creation screen to look like:
I took a screenshot from my GNex used GIMP to make it plain white, then used MS Paint and GIMP to create this, so it's not the best quality thing ever, but it gives you a general idea of what I'm thinking.
The only required piece of information would be the name. Each person needs a name, and they will be assigned an ID in the back end. I left some empty boxes, just because I don't know what else people will want to put in there.
There are also options to import information from Facebook, Twitter and Google+. This is something that I've never actually done, so I'd have to look at their APIs and figure out how to do that. (Or if it's even possible in the case of G+)
I also have achievements built into the Windows game, so I'd like to keep those and link them to a user profile as well. I also want an option for a user to backup this user data somewhere, and re-import it to a new device so that all of their hard work is not lost. Not sure if that's possible without root access, but I'll look into it.
For the picture, I'll obviously come up with a default picture like most services do. That picture will be used unless the user uploads a new one, or pulls one from a social media site.
I'm generally a fan of the dark theme, but for this application I think the light theme will be a better fit. It will give a more upbeat feeling to the app, and I just think it will look better than the dark theme. As shown in this render, I will likely still use the dark theme for the buttons. This will make them stand out a bit from the rest of the UI.