Hacker is a game in which you must 'hack' each system and gain access to it. The game consists of a main command panel in which you can type commands, some commands may bring up other user interface panels to allow you to hack in different ways. The game is a variety of technique and guessing. The best thing to type first if your stuck is 'HELP', this will normally give you a list of commands that you can use to hack with. From there you must work out your own way into the system.