SoundMUD is evolving again from the action roleplay-game branch (SoundMUD 0.9). It should become a sound-only mini-MMORPG: a text MUD with immersive positional sounds and cartesian coordinates inside each room.
SoundMUD 0.13 has a MMORPG-like gameplay: no need to hold Enter to move or attack any more, just press backspace once; special attacks or spells or actions are missing though, so the result might be unconvincing yet. Here is the manual of SoundMUD 0.13.