Riddle of the Sphinx is neither a remake of the confounding game by Imagic for the Atari 2600 nor a retelling of Oedipus saving Thebes. Instead, the game takes the plot from Infocom's text-based Infidel and adds a few twists. The game takes place in the modern day, and you play as an archaeologist visiting the dig site of your mentor, Sir Gil Blythe Geoffreys. Geoffreys has vanished just before making a great discovery regarding an artifact buried in a secret chamber in the Sphinx. He has left behind clues that you must decipher in order to finish his work. The story is little more than a clothesline on which to hang puzzles, but it serves its purpose and even manages to be involving, especially when you're listening to the tapes Geoffreys has left behind for you.
Geoffreys' voice is provided by Jeffrey S. Tobler who, along with his wife Karen, did almost all of the programming, art, and design for Riddle of the Sphinx. There are a few ancillary members of their design team, and quite a few of them also have the last name Tobler. But for the most part, this is a two-person show. It's a labor of love, and it shows. The personal nature is both what makes the game seem rudimentary and what makes it great - this isn't the kind of game you get when someone is concerned about the bottom line. Perhaps it's no surprise that the end result is really good. In particular, the voice of Geoffreys is more believable than most of the voice work in bigger-budget games. His notes to you are delivered so convincingly and naturalistically that it seems at times as if David Mamet were directing the dialogue.
Likewise, the graphics and sound are well suited to the game. The score is subtle and atmospheric, while the sparse sound effects are, if not particularly noteworthy, at least nonintrusive. The graphics make up in detail what they lack in quality. That's not to say the art direction is bad, but the low-resolution graphics do seem a bit dated. The Toblers have used Macromedia Director as the backbone of the game, and the graphic quality suffers slightly as a result. But despite the technical drawbacks, the design is great, and it features realistic environments and believable settings.