does this do anything other than unlock that achievement? i dont get the standing in a field part
No, it's actually a game you can play. It's a text-based game. You play by entering text commands on the computer (for example, "open door" or "shoot gun") and then the game will respond with text telling you what happened as a result of your commands.
Games like this were some of the first computer games developed in the 70s. They were popular up until the early 90s. There are some still around today, but now they're much less common.
I think Activision ended up owning the rights to Zork a few years back, so that's why it's included...