The Game Guru is an interesting cheat device in the sense that there's a lot more things available than your standard Game Genie or Action Replay. Sadly, it could only edit save files...and was for the 3DO.
Developer Video#
After using the Game Guru to patch GameGuru.cfg with the code IHAVETHEVIDEO2, the game goes to this half-sized FMV of one of the developers giving a tour of their house/development studio.