If an account with the provided username doesn't already exist then one will be created. Once logged in you can (optionally) bookmark the page and use that bookmark to automatically log back in.

Usernames can't be less than 4 characters long, over 15 characters, or contain any characters other than numbers and letters. Passwords are case sensitive, but usernames aren't.

This game is also available now on Steam. The Steam version can be played offline and easily modified.