I did read a game named "Terminal Boredom" for Apple II used an unofficial clone of the engine. I'm not sure what this mean, but I'm curious if this game uses the same engine or an extremelly similar one.
There are unofficial clones of the engine, such as a BASIC/6502 assembly clone for the Apple II used in a game called "Terminal Boredom."
[ ] TERMINAL BOREDOM (shareware). The object of this hi-res adventure game is to keep your on-screen alter ego from falling asleep. In addition to give him something to occupy his sleepy little mind, you'll have to see to it that he begins and completes a study of Applesoft BASIC. By Karl Bunker. Requires 64K.
i guess in this context, "clone" can be used to mean something that does the same general thing, as opposed to something that does it in exactly the same way internally. in terms of video games it's always been used this way, eg talking about a "tetris clone" or a "mario clone".