One of the cooler children's games I had for the mac in the early 1990
's. Made by Cyan
It was originally released for the Macintosh in 1991 in Black and White, and was colorized in 1993.
The game is very similiar to The Manhole or Cosmic Osmo (and the worlds of the Mackerel). There is no real objective or way to win or beat the game, you just explore. It's like Myst without the puzzles.
Funny I should mention Myst, as each scene was hand-drawn by Robyn Miller, co-creator of Myst. In Spelunx, each scene is drawn, not rendered.
There is a basic premise: Dr. Alexander Spelunx and Mr. Seudo (no, not the noder) decided to build a world away from the city and the rest of the world, so they made a big underground place to relax.
You start off at the opening gate, and see an elevator. You click your mouse to move forward, or interact with the environment, like pressing the Down elevator button. You navigate like you do in Myst.
Once you're below the ground, there are a number of tunnels to explore. There are three rooms, the Spelunx-Nemo room, the Spelunx-Arwen room, and the Spelunx-Tumnus room.
The Spelunx-Nemo room is the offices. You can go up to the observatory, or click the torches to go to the secret room below. There you can draw, experiment with gases and their lighting properties, pour coffee, drop stones and time their descent and echo, keep a journal, and bounce piggies.
The Spelunx-Arwen room is a forest. There you can compose music, make animations with stamps, and grow trees that have your design, color, shape. Arwen was from The Lord of the Rings; I learned it 9 years later, and still remembered the game.
The Spelunx-Tumnus room is the coolest. Tumnus was from The Lion, The Witch, and the Wardrobe by C.S. Lewis. You can play Yodel Toasters, time lightning bolts, and raise ants and lizards, as well as do puppet shows with your Mac's Microphone.
The point of this game was to teach a few things, while letting kids explore an imaginary world. You could learn by adjusting the thermostat that lizards move slower in the cold weather. You learned that the further lightning is away, the longer it took to hear the thunder. You can drop a pebble and learn how fast it takes the sound to return, as well as how gravity accelerates objects.
One fan site puts it best:"Unfortunately, Spelunx is currently unavailable. Professor Spelunx and Mr. Seudo are still continuing their explorations of Planet X and haven't returned yet. I hope they come back soon."