Navigate using the W,A,S,D keys. Jump using the Spacebar.
It's also possible using a gamepad (currently only tested with the Xbox 360 controller). In that case jump using the A button.
Unpack. Run the .exe in the bin/ folder.
If it complains about msvcp100.dll missing, install this: http://www.microsoft.com/download/en/details.aspx?id=14632