Summary
One Line Will Never Do ZZT Justice!
The Good
ZZT is the best of the old world of shareware from the early 1990s.
The creativity value? AMAZING.
You can create so many unique and different worlds with it. I'm serious. You can create literally anything. Objects that interact with each other. [You can't get through the palace without the red sword, etc.] Things like that. It's so much fun.
The Bad
The graphics: horrible.
The sound: horrible.
Oh well. This is from 1990. Back then, we really didn't have much in terms of power. Besides that, it was created for simplistic creations. My biggest complaint is the fact that Tim Sweeney "lost" the source code. Dear God. I have data backed up for years of other backups and you "lost" the source code to one of the greatest BBS games in history? Over 100,000 registered ZZTers!?
The Bottom Line
There's no easy way to describe it to others. Basically, it's a GCS or Game Creation System. It uses only a few colors and the ASCII characters for objects and graphics. You can get graphically creative with 3rd party addons such as KevEdit/ZZTAE/S-TOOL-K and more.
It's so much fun to sit down and create a virtual world with objects that interact. You can create something so quickly, that it's amazing!
Some of the games you might like are:
Code Red
Todd's Adventure
Burger Joint
Rhygar 1,2,3