Okay, fair enough. First, you get my standard disclaimer: This stuff isn't finalized yet. This is what is in my latest build, and could change, but this is closing in on final. And I'm not going to give you details on what each of these things are, but you can speculate, and will have more info soon.
There are three different land types (and random.) There are six different map sizes from teeny to gigantic, plus random. There are eight different difficulties and four different game speeds.
We are constantly updating the graphics and they are not finalized completely yet - with a good graphics card the rivers blend well with the landscape. (Although referring to the Newcastle shot, what do you think of that river? I can get more info on that if you would like.)
I'm not going to tell you what the tents are because there will be more details on tile improvements in the future, but suffice it to say it's an improvement that you can build around your city (like farms, for example.)