ZZT
Epic Megagames, 2001
Before Epic Megagames (creators of the Unreal series) even became known as Epic Megagames, Tim Sweeney created this relatively simple GCS which served as the inspiration for Megazeux and resulted in over 100,000 registrations by users. That's not too shabby. Even though ZZT has been eclipsed by Megazeux in terms of usability, features, graphics, sound, etc., it is still wildly popular. Also, well over 1,000 ZZT games have been created, and hundreds are available on the net! ZZT will run on almost ANY computer, so if you're looking for games for your old clunker of a PC, try ZZT ... as I mentioned, there are 1,000's of created games available. (Note: Even though the game says 'Registered Version: Do not distribute', Epic has released the registered version for free.)
[Download] Click here to download ZZT (175k)
[Link1] Click here to download games made using ZZT
[Link2] Click here for a helpful "newbie's guide" to using ZZT!
SS
Credit:http://www.dosgames.com/g_gcs.php