I used a vax for long enough where I sometimes forget/don’t consider that DOS adds .EXE 😬
I don’t have a good solution for Tab at the moment.
I got stuck very early - typing FIXTEXT.EXE (sic) HELP.TXT prints a series of gibberish in big characters and then says “Bad command or file name”,
The gibberish big text is a cryptogram puzzle. Each letter has a text field. If you type a letter in it, it will fill it in for all the same letters to help you solve it faster. Once the puzzle is solved the story progresses and another puzzle is presented.
The news command contains additional story, and includes a hint or two on the final puzzle.
I definitely could make the description and in-game help better.