Not sure if this has been answered yet or not but why is the game compressed into a .rar file? I don't have access yet to WinRAR, and I can't play the demo with out it. Why isn't there a version of the game compressed into a .zip file?

because rar file is also a common and efficient way to compress files, most people don't have any trouble with it

In fact, I think recently Windows got an update that lets you open both zip and rar without using WinRAR or any program