Spanning two games and an expansion packnote Overture, Black Plague and Requiem respectively, Penumbra is a Survival Horror series that follows physics professor Philip, who, after attending to his mother's funeral, receives a letter from his long dead father Howard instructing him to destroy a breadcrumb trail of mysterious documents without reading them. Phillip, suffering from severe Genre Blindness, instead follows the trail to a forgotten old mine somewhere in northern Greenland, where he promptly finds himself trapped and (seemingly) alone during a blizzard.Created by Frictional Games (the company that went on to make the equally terrifying Amnesia: The Dark Descent) Penumbra is also notable for its unique engine that allows solving puzzles through clicking, dragging, and directly interacting when using items, giving an especially genuine, immersive atmosphere that even earned Black Plague a nomination for best script (from The Writers Guild of Great Britain, that it ultimately lost to Overlord).
Absurdly-Spacious Sewer: A level in Requiem identifies itself as a sewer, and it has two side rooms with manholes at the top, a side room containing a generator and some transport system, and a large reservoir that you need to flood to progress to the next area. The water seems to be purified, unusual for a sewer. It follows the style meant for technical or experimental work.
Afterlife Antechamber: Requiem seems to be this. Logs from Eloff Carpenter and Dr. Eminess indicate they both showed up in the labyrinth right after you know they died and they have no idea how they got there.
All Myths Are True: There's a grain of truth in all the Inuit legends about the Tuurngait, mysterious spirits roaming the frozen wastes of northern Greenland...as you'll discover with alarming frequency from the occasionally found textbook or old newspaper article. Overlaps quite a bit with Foreshadowing.
Ancient Astronauts: One possible explanation on how the Tuurngait came to Earth millions of years ago - "before man was even upright".
Ancient Tradition / Ancient Conspiracy: The Archaic, a secret society attempting to research the Tuurngait and mainly getting itself slaughtered. They're extremely corrupt, and willing to sacrifice the lives of lower-ranking members to protect the upper echelons.
Apocalyptic Log: Over and over - this is a horror game, after all. First with Dr. Roberts' (the spider hater) insane diary, then with Eloff Carpenter (who recorded on cassette his horrifing final moments) and at last, with Philip himself.
Arson, Murder, and Jaywalking: While in the infirmary, you stumble across a note detailing when using the Cryo-stasis chamber is deemed acceptable. The list of permissible ailments include "cardiomyopathy, glaucoma, polio, diabetes, or halitosis."
Bizarre Alien Biology / Starfish Aliens: The Tuurngait are apparently some sort of sentient semi-parasitic virus from an unknown world. They also have the traditional Hive Mind element to them and are capable of altering the genetic structure and nervous system of other living beings.
Bait and Switch: At the start of Overture the player keeps finding journal entries about giant spiders and finding giant webs scattered around caves and tunnels and is then attacked by zombie dogs.
At the end, it says that he tied a noose. "Those monsters may feed on my corpse, but they won't take my life."
Bittersweet Ending: The ending of Black Plague. Philip is doomed and everyone else in the complex is dead, but Philip manages to send a message to the outside world that will hopefully cause the Tuurngait to be destroyed.
Broken Record: In Requiem, a tape player gets stuck in a playback loop on a short phrase, despite it being empty. Later, the PA suffers from the same issue, and the announcer thanks you for fixing it before continuing with the intended message.
Chekhov's Gun: Armstrong's Mixture, to some extent in Overture. Shows up as a page in an explosives manual you find very early in the game but isn't actually used until very near the end where you use it to blow your way through to Red.
Cowardly Lion: If Philip so much as looks at a monster for too long, there'll be a lens flare, and he'll freak out and give away his position. That said, he never gives up, and he thinks and fights his way out of situations that kill everyone around him.)
Cult: The Archaic Elevated Caste again. They don't seem to be explicitly religious in any way, lack any sort of unifying symbol and have few official rites, etc. They're more like a secular, Mad Scientist version of this.
Dark and Troubled Past: Implied for Philip and his father, Howard, the latter requesting that several cryptic documents be destroyed. These letters contain the directions to the Greenland Mine in which the horrible events of Overture occur.
Die, Chair! Die!: Generally averted. In the first two games, this is to your benefit, since often you'll need that chair to barricade the door against whatever is pounding it down. That said, there are plenty of breakables in the form of ketchup bottles, Scotch bottles, etc.
Diegetic Interface: Besides the inventory window (default key TAB) and an optional tiny crosshair, there is basically no HUD at all.
Door To Before: The chemical labs have an emergency door, which you can open by sabotaging the flow of chemicals in the lab itself, but only after you get past cameras, enemies, and security puzzles. And then there's the matter of going through the hallway the door leads to...
Eldritch Abomination: Just look at the description for the Tuurngait - they're pretty much Cthulhu and the Elder Gods.
Enemy Within: Clarence, the Tuurngait's personal representative within your skull. He spends half of Black Plague trying to kill you and the other half trying to keep you alive so he doesn't die too. It really doesn't help that he can give you hallucinations at will.
Fetch Quest: Done throughout (they are Adventure games, after all), and lampshaded in Black Plague.
Clarence: "Christ! Go here, go there, fetch this, run me a bath... typical broad, atypical circumstances."
Red : "Really, the hunger is becoming... rather uncomfortable here... How far away are you ? You cannnot be far. I am held captive by a wall of stone in the northeast of the mine. As in any drama, there are many roles to be played. You must act the scientist in mixing potions, act the renegade in plots of destruction..."
In other words, you need to make an improvised explosive and blast through the cave-in separating you from the part of the mine inhabited by Red.
For Science!: The Archaic, as already hinted at in the Cult trope entry.
Framing Device: The first two games are framed around an email from Philip to an unspecified individual, explaining why he failed to do something that needed to be done, and has to ask another to complete the task. The expansion pack takes place immediately after.
Grey and Gray Morality: The final choice Philip is presented with in Black Plague. If he had done as the Tuurngait wanted and asked the reader to remove all evidence of the Shelter, the Tuurngait, who seem a little too eager to assimilate the "invaders", would stay alive, likely indefinitely, and the Shelter would become a second tomb for the Tuurngait. When he asks the reader to have the Tuurngait destroyed, he is killing off an ancient and wise being older than man that sowed pieces of its knowledge into our species.
His Name Is...: Eloff Carpenter records his final words on a cassette tape and says he knows the primary weaknesses of the Tuurngait, but before he can spit it out he's apparently dragged off and killed. "The species' primary weakness is—uugggh!"
100% Completion: In Black Plague, statistics at the end tell you how many artifacts and documents you collected. Requiem just has artifacts, but they actually serve a purpose - collect them all, and you unlock the Golden Ending.
Improvised Weapon: You don't Drop the Hammer, you swing an actual hammer. Later on you find a small pickaxe (or ice-pick), but you're still pretty heavily outclassed. Then along comes the second game, which offers you no straightforward weapons at all. As in Overture, you can still stun enemies by throwing objects at them, but other than that, you can only rely on your own feet and the patient use of stealth this time.
Word of God stated that the weapons were removed because they were intended to be used for defense, but turned into a Cherry Tapping tool.
Mysterious Antarctica: Not set in Antarctica, but still a great Video Game example of the "arctic wastes horror" genre. The whole series takes place in an unspecified location somewhere in the far north of Greenland. The atmosphere is captured brilliantly - from the very arrival aboard a chartered fishing boat to the discovery of the secret base's well-hidden entrance.
Sandworm: Or more precisely, a "giant gray rockworm". The real Invincible Minor Minion, and it can also kill you in one hit. Fortunately, there are only two or three of them.
Save Point: Voluntary savepoints are done in an interesting fasion: They're ancient cylindrical lantern-like artifacts apparently brought to Earth by the Tuurngait and later rediscovered when the mine and underground base were built in the 20th century. Unfortunately, these strange objects help the Tuurngait see into your mind and secretly infest it.
Screw Destiny: One possible way to view the ending of Black Plague is that Phillip refuses to be the Tuurngait's pawn.
Shout-Out / Homage: Lots. For instance, Howard's and Philip's names hint at H. P. Lovecraft himself, and the Archaic's library contains copies of The Necronomicon and De Vermiis Mysteries.
Several food cans are labelled Uncle Cthullhu's Squid Soup".
The crowbar from Overture, needed for solving a puzzle, was previously owned by some long-dead arctic explorer named Freeman.
In Black Plague the Infected have a blood goatee, Black Eyesof Evil (which resemble glasses from far away), and some wield crowbars.
The Donkey Kong like area in Requiem, where flaming barrels roll down several vertically adjacent slopes while music that sounds suspiciously familiar.
Silent Protagonist: Philip is an interesting subversion, since he narrates the intro cutscenes and you can read his thoughts and ideas about an object or situation in-game after clicking the right mouse button.
Stealth-Based Game: You can try to fight anything you come across, but considering that you only have a pickaxe, do you want to ? Not to mention that you're utterly weaponless in the two sequels (if you don't count object-throwing).
Philip even shows his Genre Savvy side and lampshades the need for stealth in one of the earliest levels of Overture (where things start looking really serious).
Tempting Fate: Traveling on your own and completely alone to the most isolated regions of Greenland in search for answers about your father's mysterious past requires either utter Genre Blindness or "I've got nothing to lose" sentiments.
Ten-Second Flashlight: In the first two games. Requiem uses an Infinite Flashlight (if you're hallucinating it all, no need to hallucinate battery charge drain). Averted though with the glowstick, which Philip begins the game with. It casts a shorter and dimmer (though more peripheral) range of light than the flashlight, and never runs out.
The Other Darrin: Philip has a vastly different voice actor in the English version of Overture and Black Plague. All the more strange, since the rest of the voice cast remains the same throughout the series.
Overture had a tiny, yet effective voice cast of two people. The Overture incarnation of Philip (though uncredited) was voiced by Tom Jubert, the script writer of the series (since Frictional had little budget to create Overture and could afford a larger voice cast only after the game achieved success). Many fans consider Overture's Philip to be the canon version, since he at least sounds like an Englishman in his 20s or 30s, unlike the suddenly North American-accented 40s-sounding Philip from Black Plague.
Unobtainium: The Archaic has discovered seventy different kinds.
Video Game Cruelty Punishment: In Black Plague you can set a Tuurngait on fire at one point. Then it turns out there's a door right behind it that only a zombie would be strong enough to tear down.
Especially bad if you pulled the lever to find out What Does This Button Do?, as the Infected will walk right into it. Then the puzzle can't be solved without taking the same approach to a different lever.
Voice with an Internet Connection: Subverted in Overture - Red can only contact you via walkie talkie, has no idea where you are or whether you're still alive, but he's so lonely he keeps talking. Played straight with Amabel Swanson in Black Plague, and sort of bent in Requiem as Red, Dr. Eminiss, and the bland voice on the intercom all counsel and taunt you.
Violation of Common Sense: Well, it fits the theme, but one puzzle requires you to set yourself on fire so a trap will malfunction and someone else can get through it safely. Incidentally, stupidity is not the only option—it's just the only moral one (as well as the only one that allows you to go on with the game).
Not to mention another puzzle where you have to inject yourself with an unknown chemical in order to put yourself in a chemically-induced coma so that the door you need to go through will be unlocked. The function of the item is actually explained in a nearby note, but it is entirely possible to miss it and arrive at this result anyway through good old experimentation.