Each room contains interactive mini-games and experiments, most of which introduce the player to a specific field of knowledge.

The game was programmed and implemented using HyperCard, with Robyn Miller hand-drawing all of the in-game graphics and scenery.

The game's title was derived from the verb "to spelunk", referring to the act of exploring caves.

Computer Gaming World stated that Spelunx would "provide hours of entertainment in a variety of ways for both children and adults".

Although the original monochrome version contained small amounts of color at specific locations or during specific events (utilizing MacroMind Player, a predecessor of Adobe Flash), this new version (colorized by artist Josh Staub) contained full-color scenery and animation (as well as a small easter egg: an image of Myst Island hidden within one of the original rooms).