Z-Machine - makes playing the classic Zork interactive fiction game possible and easy on Android devices.

Z-Machine is not the game itself and does not contain or require any ROM to play.
Z-Machine simply provides an interface to the publicly available Internet Archive posting of the streaming version of that game found here: https://archive.org/details/msdos_Zork_I_-_The_Great_Underground_Empire_1980

This requires internet to load, but does not use any data after that.