You need to files to have the correct client to play, both of which are below. The demo which was made freely available and a patch tool create by the team.
Currently there are no public test servers to play on
Game Demo Download
Game Patch-up
After that edit the shortcut for the game to add the following to the target after the closing "
/NoPatch /AuthServer=IP:Port
IP is the IP address of the server, such as localhost
Port is the open port the server is listening on.