Needs A Better Description, Rolling Updates, How Did We Miss This One A trope often seen in Video Games, the bane of every Pacifist Run, and a moderate annoyance for some Speed Runners. We are talking about doors, treasure chests and all sorts of locks that won't open until you kill the enemies surrounding it, as if this seal's integrity was somehow linked to the life of the entities surrounding it. Usually the character has to kill every single enemy in the room/level in order to defuse the lock, but some times it might require just a percentage of them, or the elimination of a specific type of enemy. (usually an Elite Mook of some sorts) Teleporting Keycard Squads have a tendency to invoke it when they appear, in order to force the player to fight them. Also quite common in Boss Battles, as way to prevent the players from escaping or "unfairly" exploiting the environment to their advantage. May induce Fake Longevity if abused or poorly implemented, as in games that hide enemies to force to backtrack. A sub-trope to Cruelty Is The Only Option and Plot Lock. Related to Plot Sensitive Latch. Compare with No Ontological Inertia.
Examples:[[foldercontrol]] [[folder:Video Game Examples]] Action Adventure
- Most of the games in the The Legend Of Zelda saga make use of this trope. Usually, the locks activate after you find an important treasure, or just before you get said treasure.
- The Metroid series uses these a lot, usually in the multiple pirate bases you'll have to raid. Also an egregious case of Fridge Logic, because unlocking the door for someone who has just murdered your security team seems like a genuinely awful idea! The science Team has vapor for brains, indeed...
- Star Fox Adventures has its own share of Life Force Doors. They look like red vortexes with a skull in the middle and little "spirits" orbiting around it. That last detail actually has a purpose, as the number of "spirits" indicates how many enemies you need to kill to open it.
- Whenever a battle starts in the God Of War games, every possible escape route is covered with a wall of flames. The flames vanish after all enemies are slain.
- Doors in the Devil May Cry series will sometimes become locked with magical barriers, requiring you to kill all the demons in the room before proceeding.
- Ever Quest had a variation on this. The insanely powerful but mostly insane prismatic dragon known as Kerafyrm was put to sleep by Veeshan, the God of Dragons for his crimes against dragonkind. The catch was that four dragons had to spend the rest of eternity as warders to ensure that the spell keeping him asleep was never broken. Players had to kill all four warders in order to wake him up... but the first few guilds in the game to do so quickly found out that waking him up was a bad thing. Kerafyrm would rampage out of the tomb, go over to the city of Skyshrine and go on a rampage there, and then go on a rampage in the Temple of Veeshan before finally leaving for good. This happened once and ONLY once per server. The Warders, who contained exceptionally powerful loot, were dead for good.
- In Rayman Origins in order to rescue the Electoons, you need to dissipate bubbles of dark energy surrounding them by killing the enemies connected to it, (as it seems their life-force is the thing powering the barrier via streams of darkness) before smashing their steel cages to bits.
- The Binding Of Isaac makes ubiquitous use of it, as every room containing enemies will automatically shut itself down until you kill them all. However, the game also features a twist to it, as it's possible to force your way out of a room containing enemies by blasting the door with a bomb. (Either yours or fired by an enemy)
Of course, this tactic must be used sparingly because bombs are a precious commodity most of time, and doing so doesn't take care of the enemies inside the room, so if you walk back into it, you'll either have to deal with the enemies, or use another bomb to escape once again. Also, this tactic doesn't work in boss' (nor mini-boss') battles, because their doors are blast-proof... Just like every single door in the game's Brutal Bonus Level.
- Jet Force Gemini is the Trope Namer of sorts, as it features obstacles called Life Force Doors which can only be opened by killing enemies.
- A staple in the Mass Effect series, where you usually required to clear out each room before you are allowed to proceed.
- Rock Solid Arcade's Web Game Robokill. When you enter a new room there are no exits. You must kill every robot in the room before the exit(s) will open.
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