Twisty is an open source Android interpreter app released by Google employees (opening says "(C) Google, Inc.") in the early days of Android. Version 0.82 is the current version on the Google Play store.
An enhanced version is mentioned on the Google Play listing as a development work in progress. Anticipated changes are added Glulx support and a faster, compiled C code, Z-machine interpreter. A pre-release APK for Side-loading has been published on Github.