SWAT: Elite Force is a massive overhaul of the base game mechanics, making it into a more realistic tactical police simulator, with added traps, equipment choices, and new ways to play the campaign. In addition, it adds important quality of life features which are necessary to play the game.
Instead of one global administrator password to rule them all, server hosts can create a series of roles, each with their own password. By logging in with the correct password, a player can assume that role.
Additionally, there is the "Guest" role which is available to all players, without logging in.