Tenebris Somnia Achievements — Full List and How to Unlock Each One

Tenebris Somnia has 30+ achievements split into story progression, sidetrack (many missable), combat, and four endings. Each section below lists the achievement, what unlocks it, and whether it is missable. The four endings persist on the Steam profile as SOLVE ET COAGULA, MAGNUM OPUS, VIVUS EX MORTIBUS, and RENUNTIATIO.

• Devora — Find all three Film Canisters: the Devora 1 in Iván's Floor 2 chest, the second in Iván's childhood room after Floor -1, and the third Cursed Film Canister after purification with Purified Water. See film canisters.
• Have You Chosen… Wisely? — Use the Silver Bottle on the three apartment save points (Floor 2 bedroom, Floor 3 office, Floor 2 director's office) to fill it with three doses.
• De Relictis — Read every page of the Old Book before the run ends. Required to make Endings #3 / #4 eligible on that run.

• Maybe He's In The Bathroom (Missable) — At the very start of the run, interact with Iván's closed door 10 times instead of using keys. Once you unlock the door the normal way the chance is gone.
• Thinking About Him, huh? (Missable) — On the 2nd floor apartment, find the picture in the computer room and interact with it 5 times.
• One More For The Road — Drink Lavendoleum while at full health.
• Classics Never Die (Missable) — Pick up the Iron Pipe from the bathroom by first grabbing the Screwdriver from the box near the film reel viewing area; without the Screwdriver the Pipe can't be acquired. See Iron Pipe weapon.
• Stella Plena (Missable) — Open all 6 star lockers before the Sanguis beast-form boss fight. The last star locker must be opened before that point of no return.
• Bad Puppy (Missable) — During Sanguis's beast-form fight, bait his attacks into the standing mannequins until he breaks them. Don't kill Sanguis accidentally during this redirection. See Sanguis beast form fight.
• You Can Stop Now (Missable) — In the infinite green corridor puzzle, keep going left until the achievement pops.
• Heart of Lead (Missable) — Going for Ending #2, kill Relicta ghosts on every floor, not just on the path to Séptimo Arte. Avoid multikills and wait for the gold particles to clear between kills. See endings.

• Wrench Queen (Missable) — Complete the game using only the Wrench. No shooting or aiming other weapons at any time. See Wrench weapon.
• He Just Wanted a Hug — Damage a Vorax until it turns red, then flee to another room before it self-destructs. See Vorax fight.
• The Two Stooges — Kill 2+ enemies at once (not Carnitos). Easiest in narrow hallways near elevators by letting enemies stack first.
• Iron and wax (Missable) — Defeat Obscuratus (1st boss, candle room behind the boarded window) using only the Wrench. See Obscuratus fight.
• Exhaust Pipe (Missable) — Defeat Fumus (2nd boss, animal skull key door, hole in face) using only the Pipe. This run invalidates Wrench Queen. See Fumus fight.
• Valiant Little Taylor (Missable) — After picking up the Cold Chisel and opening the boarded door, stack Carnito-spawned enemies and kill at least 3 with a single hit. See Carnitos fight.
• Butcheress (Missable) — Defeat Carnitos without ever being hit. Stand at the bottom-right corner blind spot of the arena; let Carnitos whiff melee into the corner, then punish between attacks. See Carnitos fight.
• Acrophobia (Missable) — During Lacuna Phase 1 (Ending #1, Good), stay still during her scream-jump-land so her grab kills you. Must be done deliberately.
• Devoured (Missable) — During Hermes Phase 2 (Ending #2, Bad), walk into the boss's mouth and die. Must be done deliberately.

• SOLVE ET COAGULA — Ending #1 (Good): after forging the Aurifer Knife, don't kill Relicta ghosts; sprint to the Séptimo Arte building for the final boss.
• MAGNUM OPUS — Ending #2 (Bad): after forging the Aurifer Knife, kill several Relicta ghosts with the Aurifer on every floor along the route; combine with Heart of Lead for the maxed kills.
• VIVUS EX MORTIBUS — Ending #3 (Secret): requires Endings #1 and #2 first. Start a new run, pick up the book (De Relictis achievement), then use the bible on the TV static screen (follow the symbols shown), on the Community Center reels, and on the Floor 0 green door (cycle the camera 6 times). Collect the inverted red crosses that appear and place them outside Séptimo Arte to trigger Ending #3.
• RENUNTIATIO — Ending #4 (Secret): requires Endings #1 and #2 first. Start a new run and, instead of progressing through the building, use the keys you already have to leave the apartment complex immediately.

De Relictis must be earned in the same run that unlocks Endings #3 or #4, otherwise that run doesn't count.

Many of the achievements above conflict with each other:

• Wrench Queen and Exhaust Pipe require different weapons for entire fights.
• Iron and wax requires the Wrench on Obscuratus; the same weapon selection rules out other weapons for that fight.
• Acrophobia requires dying during Lacuna Phase 1; Devoured requires dying during Hermes Phase 2 — these are separate runs.
• Heart of Lead requires killing Relicta ghosts on every floor for Ending #2; SOLVE ET COAGULA requires not killing any. Branch from the same save after the Aurifer Knife is forged.

Plan the missable steps across separate runs and reload to switch between the Good and Bad ending from the same Aurifer save. See endings for the exact branching point and combat strategy for the weapon-aware rules.