Ned the Knight did a lot with a little. Sword-swinging-y ARPG gameplay, essentially ASCII Zelda. (Sword swinging wasn't a default behavior available in ZZT, but it only takes about 15 minutes of simple scripting to script it in). I wish there were middleware out there to build something like that, but multiplayer.
For a more puzzle-y focus, here's a video of an old ZZT game called Winter, which has no combat, only puzzle solving: