Spelunx and the Caves of Mr. Seudo

Spelunx and the Caves of Mr. Seudo is a 1991 educational HyperCard adventure by Cyan, designed by brothers Robyn and Rand Miller for young children. Players wander a network of hand-drawn underground rooms via a central elevator, opening interactive experiments and mini-games rather than racing toward an ending.

A Cyan title before Myst

Built two years before Myst made Cyan a household name, Spelunx already shows the studio's signature first-person, point-and-click exploration. Robyn Miller hand-drew every scene; the loose frame story stars Professor Spelunx and the mischievous Mr. Seudo, who serve as guides rather than antagonists.

HyperCard under the hood

The original 1991 release shipped as a black-and-white HyperCard stack and ran on the era's compact Macs. Each room is a card, each navigable hotspot a HyperTalk script, which is exactly the construction Cyan would scale up for Myst.

Rooms as toys

The caves are organised as themed rooms reached from a shared elevator: an Animation Machine for stop-motion, a telescope, the Yon-Yon Caverns demonstrating gravity, a Lightning Simulator for the speed of sound, the Pigtoad Tree for music and rhythm, plus genetics and animal-behaviour stations. Cyan billed the game as something to be explored rather than completed or won.

Colour version and afterlife

Following Myst's success, Cyan reissued Spelunx in 1993 with full-colour scenery and animation, and later ported it to Windows. The colour version is bundled in Cyan's Complete Pack on Steam, keeping the title in print decades after its HyperCard debut.