You're a future hacker (it's 2054). You work for a corrupt organisation called 'The Company', who tell you to do hacker-type things on the 'net (colled Globe Net in the year 2054). If you do the things they tell you to do you get some money and the chance to do more things.
The one mission included with Access Denied involves you tracking down a floppy disk which contains a logic bomb, that you need to set off, in the source code of a programme which has been designed to fight all viruses. This then involves you taking text-only cab rides to Cyber pubs and Cyberbanks, text-only interaction with a few people before logging on to Globe Net and doing various bits of simple detective work to hunt down passwords and other bits that enable you to proceed further. And that's the basic problem. Just when you think you're starting to get somewhere and are actually having a kinda text-only bit 'o fun you discover you've done what you're supposed to do and the game comes to a complete stop.
The hardest part of Access Denied, and in fact the only reason why it takes that long to play is because there are screens and screens and screens of text to be read. It's not innovative or full of amazing visuals (ahem) or anything, but it's better than your average PD offering in this vein.