TUNNELS OF DOOM
Tunnels of Doom was a 1982 module made by Texas Instruments for the TI99/4 computer and was created by Kevin Kenney. The module contained code which required the loading of game data from cassette or disk. A sample adventure was sold with the module on disk or tape but subsequent adventure databases were developed by individual users using back-engineered editor programs.
The module did not have an immediately playable game when you plugged it in, it required you to load a database from tape (slow) or from disk which was somewhat expensive (at the time) as costly peripherals were required which were not widely owned.
A UK computer game magazine was unimpressed and only gave the module three stars out of five, but it has proved popular with TI owners and has remained in play with quite a number of user written adventures being made available. The game has been so popular it has been recreated in java.
Java: Tunnels of Doom Reboot (http://www.dreamcodex.com/todr.php) by Howard Kistler (with Kevin Kenney's agreement), also has a conversion tool to allow the older third party adventures to be converted.
Main gameplay was through the module, while game items- names, values, powers, graphics - were stored in the external databases and could be edited using verioud programs which were developed by third parties.
Although the Wizard character (or equivalent- the name could be amended) had limited defence capacity, the base coding left a gap for the Wizard - or any other player- to have armour with a rating of up to 37.
An online manual is held by the Museum of Adventure Game History at https://www.mocagh.org/loadpage.php?getgame=tunnelsofdoom (click the pdf icon)