- Rhem, 2003
- Rhem 2: The Cave, 2005
- Rhem 3: The Secret Library, 2008
- Rhem 4: The Golden Fragments, 2010
Each game generally involves visiting the titular country by rail car in search of a Dismantled MacGuffin for archaeologist brothers Kales and Zetais.
In 2016, there was also an Updated Re-release of the fourth game, RHEM IV: The Golden Fragments SE, followed in 2017 by RHEM I SE: The Mysterious Land, 2018's RHEM II SE: The Cave, and RHEM III SE: The Secret Library in 2021.
The Rhem games contain examples of:
- 100% Completion: Rhem 3 has an optional bonus puzzle to be solved at the endgame, which leads to a Developer's Room containing photo albums of all 3 games, and a Sequel Hook from Kales.
- The Special Edition versions of every game include a similar bonus puzzle as well.
- Air-Vent Passageway: Used in the second game as a secret passage back to the starting level.
- The Aloner: The story gradually unfolds that Kales had been marooned on Rhem for some time, with your presence needed to unlock more portions of the country. By the fourth game, you're actually able to free him.
- Apocalyptic Log: Rhem 4 includes a journal written by Kales entailing his research. He takes it when you aren't looking after a certain point, and adds more entries at the endgame.
- Ambient: The third and fourth games add a minimalist, industrial soundtrack for atmosphere.
- Anti-Frustration Features:
- The third and fourth games include the ability to copy clues down in-game.
- Rhem 1 SE includes a few shortcut mechanisms to alleviate some of the game's backtracking.
- Rhem III SE bypasses a door puzzle after the player solves it for the first time.
- Beautiful Void: Rhem 1 seems like this throughout most of the game, apart from the one character who steals your rail car at the beginning. Then you start to come across the cave inhabitants in the later games.
- Book Ends: Each game begins with a rail car ride into Rhem, and ends leaving it.
- Broken Bridge: One of the series' staple puzzles, ranging from rotating bridges that can only be operated from one side, to floating bridges that require a certain amount of water to cross.
- Call-Back:
- Rhem 3 has framed screenshots of the first two games, and Kales' iPod contains video clips from them as well.
- Kales' last journal entries at the end of Rhem 4 reference the stolen rail car from Rhem 1.
- At one point in Rhem 3, the player can find the fourth part of the rotating bridge at the end of Rhem 2, which would've been accessible then if the Lady in Red hadn't cut the power.
- Closed Circle:
- On your ride into Rhem in the first game, a crashed rail car can be seen near the end of the track. Later, the owner of the crashed vehicle shows up, explains his desperation to escape, and steals your rail car to do so, marooning you on Rhem.
- In the later games, some contrivance is set to prevent you from leaving until the endgame.
- Door to Before: Finding doors that loop around to previous areas often indicates the presence of a hidden clue on the other side.
- Drone of Dread: 3 crystals in Rhem 2 emit an eerie humming sound when tuned correctly.
- Early-Installment Weirdness: The first game is rendered at a lower resolution than the later titles, has more Backtracking between locations, and a Myst-style flyby at the very end.
- Enter Solution Here: Most of the puzzles involve exploring to collect information, to be entered at a certain location to unlock more locations or retrieve parts of the MacGuffin.
- Epilogue Letter:
- Rhem 1 involves collecting four pieces of a letter to Zetais. You can read it at the end, largely serving to frame the second game.
- Zetais sends you letters at the start and end of Rhem 3 and 4.
- This is also used in Rhem 2 SE, replacing the live action cutscenes of Zetais used in the original.
- Featureless Protagonist: You have no identity or name throughout the series. By Rhem 4, Kales calls you "The Messenger" in his journal.
- Fictional Painting:
- Several rooms in Rhem 3 contain a variety of paintings that contain clues to other puzzles.
- Subverted in Rhem 4, where a gallery features edited versions of real-life portraits, including a few by Holbein
.
- Fun with Subtitles: Subtitles for the characters are shown in one solid paragraph on-screen.
- Ghost Butler: Most of the doors in the series close on their own after you pass through them. Doors that don't automatically close usually have a clue on the other side, or block something when open.
- Great Big Library of Everything: The third game, titled The Secret Library, has such a location a third of the way in, whose books hold clues for a large chunk of the game's puzzles.
- Indo-European Alien Language: The minute you meet her face to face, the Lady in Red talks to you in an unfamiliar, German-esque language. By the third, a different, but similarly dressed woman speaks English.
- Insurmountable Waist-High Fence: Water in the series is treated as a No Walk Zone. Most egregious in the first game, where it has to be lowered just to cross five feet between a pair of ladders.
- Lady in Red: A few are revealed in the second game onwards, which Kales believes are Rhemian natives. You actually meet one of them up close in the second and third games.
- Logo Joke: In the GotGame Entertainment release of Rhem 3, the company logo appears from a ball of light, pulsing in time with the game's theme music.
- MacGuffin Escort Mission: At the beginning of each game starting from Rhem 2, Zetais sends you off with an item to use in Rhem, and Kales gives you your main objectives upon arrival.
- The Maze:
- The Glass Labyrinth in the second game qualifies, compounded on with doors that open and close like an airlock.
- The entirety of each game could qualify, as they are laid out in highly geometric ways. And in many of them, you have to find a way back to the start, close a door or flip a switch, then circle back around to see what changed on the other side.
- Message in a Bottle: The first game has a puzzle in one area where the player has to fill a well with enough water to be able to reach a bottle that has a clue inside.
- Minecart Madness: Rail cars are the primary Rhemian mode of transportation.
- No Plot? No Problem!: Despite having similar gameplay mechanics to Myst, Rhem has very little in terms of a story, beyond fulfilling Kales and Zetais' work.
- Reaching Through the Fourth Wall:
- Near the end of Rhem 2, the Lady in Red reaches into your inventory and takes the keycard to your rail car, then hands you a token and releases you from the prison cell you fell into. She gives you back the card in exchange for the MacGuffin after you photograph it.
- In the original version of the same game, Zetias hands you a live action prop of another MacGuffin at the start, which becomes a digital icon in your inventory. At the endgame, the same plays in reverse with him picking up the photograph you took in-game. The SE version replaces this with the Epilogue Letter entry above.
- Sequel Hook:
- Around Rhem 3 are star-shaped keyholes on several devices and doors, with the bonus puzzle implying that a key for them would show up at some point. Rhem 4 never reveals this key, though Kales admits in his journal that he couldn't find it.
- The added bonus puzzles in each Special Edition version unlock pieces of a medallion to be used in the upcoming Rhem 5.
- Songs in the Key of Lock: One puzzle in the fourth game involves playing eight tones on a set of bells, first heard from a vinyl record.
- Unbroken First-Person Perspective: One of the series' Myst-like elements.
- Underground Level: The second game largely takes place in underground caverns.
- Zip Mode: A limited variant, where a special set of diagonal cursors allow the player to turn 90 degrees around corners.
