Today, for your edification and amusement, I present 2 Games:
The Hitch-Hikers Guide to the Galaxy and
The Hitch-Hikers Guide to the Galaxy.
Scores and positions in the two different games are interchangeable - you can start in one, then switch to the other, then back again. Which is improbable, but not infinitely so.
These are based on the old Infocom publications, from way back in 1984. I used to have one for the C64 (IIRC), on 5 1/4" Floppy (remember those?). Maybe in the new version(s) I can finally follow Marvin through the sliding doors...
Hat Tip : TramTown. Told you I should have gone there more often.