BTZ's first game, Mindwheel, boasted that it could recognize over 1200 words. It also tried to react intelligently to natural English input my guessing what the player meant by recognizing key words. This was partially good, since a player could type 'toad "what is west of here?"' or 'singer "what should i do now?' and had a chance of being understood. This was also partially bad, since the game rarely admitted that it didn't understand the player; this sort of Eliza-like handling of input has been called a "lying parser".
BTZ games ran in real-time. NPCs could enter and leave, and atmopheric messages might be displayed whether or not the player typed anything. However, the story itself did not advance without player input.
- if yr cmptr cn rd ths... by Shay Addams for Computer Entertainment, August 1985. Details the mid-80s "parser war" between various publishers of text adventures.
- "Building a Better Zork", Computer Entertainment, June 1985.