It was the engine I used for my very first all-text DOS game. In fact, that was the very first DOS game I ever created.
It is VERY simple and limited, but there are a number of tricks you can use to allow it to do so much more: elevators, conversations with monsters, flying in a three-dimensional area, items placed that you cannot just take without searching first even if you know they are there, six+ lines for room descriptions, etc.
It’s a great little engine for quick but fun games, and if it can in fact handle 500 rooms they can be quite extensive too.
If I ever played a TextWorld game for MS-DOS, I wasn’t aware it was made by that system. I recall a lot of one-off text adventures floating around in the late 80s and early 90s, almost all shareware distributed in the BBS scene.
When I searched for TextWorld I found this unrelated project from Microsoft Research:
No, that is not it. It has the same name but is absolutely not the same one.
This TextWorld was programmed by someone called “White Divine” around 2003. Apparently it is an enhancement of something called CIA (“Create Interactive Adventures”). It was a truly limited system only capable of something like 35 rooms at most; TextWorld can handle 500.
To be honest, from what I see so far with MS TextWorld the instructions are not overly helpful and the engine is not especially impressive. AGT has its quirks to be sure but it seems capable of more, just like TADS.