This looks like MUD, but actually it's MicroMUD, written by Jon Stuart and Paul McCracken. This was a Commodore 64 version of the game that could be played single-player (with other players controlled by the computer) or multi-player (by daisy-chaining serial ports together). It was an amazing piece of work, given the constraints of the 64 — Jon and Paul used the memory on the disk drive controller to squeeze as much in as possible.
MicroMUD was released in 1987, at the end of the heyday of text adventures. Several reviewers thought it was supposed to be a text adventure and judged it as such, giving it low ratings. This didn't stop it winning awards, though!
If it had come out maybe a year earlier it would have sold more copies, but when it finally hit the shops the move from text to graphics was well under way and it didn't have the sales it might have done. I don't think Jon and Paul made much money from it (their agent, on the other hand...).
If you're interested in taking a look, the code is available here and the emulator to run the code is here. It's a real blast from the past for CBM64 users.
What's that? Did I play it myself? Nah, I had an Atari ST.