Cosmic Osmo and the Worlds Beyond the Mackerel is a graphic adventure computer game for the Macintosh computer line (Plus, SE, SE/30, II Series, Classic, LC) created by Cyan, Inc.. It was published in 1989 and won the 1990 Mac User award.
The game features a point and click interface. The player clicks on various elements in a scene to trigger events. To move between scenes and rooms, the player clicks on doors or near the edge of the screen.
The game begins when the player enters an animated spaceship hovering in front of the title screen. While inside the ship, he can trigger various events.
The spaceship gives the player the ability to visit various planets. Aside from using the ship to move between planets, a complicated network of shortcuts exists between planets and scenes. The game, being presented in first person view, enables shifts from the macroscopic to the microscopic level. Most of the shortcuts are found at the microscopic level; through a water drain or a mouse's hole, for example.
Source: Wikipedia, "Cosmic Osmo and the Worlds Beyond the Mackerel", available under the CC-BY-SA License.