Like its predecessor, Riven is a point and click adventure game played from a first-person perspective. The player explores immersive environments depicted through a large series of computer generated stills using mouse clicks for movement or to manipulate objects within reach. By operating mechanical contraptions and deciphering codes and symbols discovered in the surroundings, the vaguely explained goal can eventually be reached.
To navigate the world, the player simply clicks in the direction they want to walk or turn. The mouse cursor changes in appearance, depending on its position on the screen and what it is hovering over, to show what effect clicking will have. For instance, if the player positions the cursor hand near the side of the screen, it may show a pointing finger, indicating that clicking will turn the view in that direction. The cursor also changes in context to show when players can drag or toggle switches, or when certain items can be picked up and carried. Such items can then be examined at any time, and either reveal clues to puzzles or provide information on the game's setting and story. Like Myst, Riven has an optional method of navigation known as Zip Mode, which allows players to skip to areas already explored, but may cause them to miss important clues.
Riven has more complex and numerous puzzles than its forerunner and is set in a larger virtual world for players to explore. Whereas in Myst the objective of the game is to travel to different Ages to solve puzzles before returning to a "hub Age", Riven's gameplay takes place on the five islands of the Age of Riven. Much of it consists of solving puzzles to access new areas of the islands, though players are also able to explore without fulfilling objectives. The volcanic landscape depicted, with its steep cliffs and crater lakes, is bestrewn with mechanical, Victorian-style artifacts such as elevators, pipes, levers and roller coaster-like transports. To solve the game, players must consider the purpose and physical principles of these artifacts as well as their role in the fictional culture.
Riven's story continues where Myst and its companion novel, The Book of Atrus, left off. The player assumes the role of the Stranger, the protagonist of the first game and friend of Atrus (Rand Miller). Atrus knows the ancient art of creating "linking books", specially written books that serve as portals to other worlds known as "Ages". Atrus needs the Stranger's help to free his wife, Catherine (Sheila Goold; voice by Rengin Altay), who is held hostage in her home Age of Riven, which is slowly collapsing. Her captor is Gehn (John Keston), Atrus' manipulative father and self-declared ruler of Riven. Thirty years earlier, Atrus and Catherine trapped Gehn on Riven by removing all of the linking books that led out of the Age; the very last book to be removed, linking to the Age of Myst, was the one they held to escape Riven. In the belief that it would be destroyed, they let the book fall into the Star Fissure, a rift leading out of the damaged Age of Riven into a mysterious, space-like void. Catherine was later tricked into returning to Riven by her sons, Sirrus and Achenar, whereupon she was taken hostage by Gehn. Eventually, the player discovered the unharmed Myst book, leading to the events in Myst.
At the beginning of Riven, Atrus equips the player with a trap book—a snare that functions as a one-man prison, yet looks identical to a linking book—and his personal diary. This diary summarizes the history of events leading to the present situation; Atrus cannot explain in depth as he is engaged in rewriting the descriptive book of Riven, in an attempt to slow its deterioration. The player must enter the Age with no way of leaving, as Atrus cannot risk sending a real linking book to Riven until Gehn is safely imprisoned lest he use it to escape Riven. Instructing the player to capture Gehn in the trap book, find Catherine, and then signal him, Atrus holds out the link book that will transport the player to Riven.
Once there, the player explores the islands of Riven, eventually discovering Catherine's prison. The player also travels to Tay, the Age of the Moiety (rebellious Rivenese under the leadership of Catherine who are attempting to end Gehn's tyrannical rule), and the "233rd Age", Gehn's personal sanctuary, where the player meets Gehn himself. Gehn attempts to convince the player that his intentions to rebuild D'ni were honorable and that he seeks atonement for his past transgressions. Because of the decay of Riven's structure, the only way to clearly signal Atrus is to bring about a massive disturbance in the Age's stability—accomplished by reopening the Star Fissure, which Gehn had closed. When it opens, Atrus immediately links to Riven to investigate and meets the player at the brink of the Fissure. Depending on the player's actions, the ending to Riven varies. In the best ending, the player tricks Gehn into the prison book and releases Catherine. Atrus and Catherine thank the Stranger before linking back to the Age of Myst. The Stranger then falls into the Star Fissure to be taken on the path back to his world. The worst ending involves neither capturing Gehn nor releasing Catherine, which allows Gehn to kill Atrus (and then the player) and escape from his imprisonment. Other endings include capturing Gehn without saving Catherine, being trapped in the prison book, or even death.