Released for Windows and Macintosh,[1] the game follows an oversized, anthropomorphic snail named Mortimer, who seeks to save a fantasy world's animal population.

[2] Players pilot Mortimer - whose shell can transform into an aircraft or submarine - through a 3D world, while solving riddles and learning simple biology.

[4] Having chosen a player-character ('Sid' or 'Sally'), the player assumes a first-person control (except during cinematic sequences) to guide Mortimer through four ecosystems (savannah, taiga, Polar Ice Cap, and desert).

During travel, the player uses its cursor to revive individual animals native to the habitat, earlier identified as changed into stone figures of themselves by antagonist 'Lodius'.

Laslow), the player rejoins Mortimer, whereupon Lodius, attempting to petrify the player-character, changes himself into a statue, with which the protagonists return to the beginning.