So Much for Stealth in Video Games.
- Alpha Protocol: Brutally beat a guard into unconsciousness with your bare hands? No problem for the guys in the next room. Walk around at the same speed and path as the guard you just knocked out? They'll all come running.
- Code Name: S.T.E.A.M: If any agents get noticed by the aliens, they'll inform the others that they've been spotted. John Henry even says the trope name at times.
- Deus Ex Universe:
- Deus Ex: Make audible metallic clunks as you sneak through vents? Okay. Drop a cardboard pack of cigarettes from a crouching postion two rooms away? "What was that noise?"
- Deus Ex: Human Revolution: Guards are often overly sensitive to sounds you make, even when the situation doesn't call for it. If there are footstep sounds from the bathroom, somehow they immediately know it's you and not a civilian worker or another guard tending to their business. It seems even more glaring given that they don't notice many things which are highly suspicious, like huge crates mysteriously moving around while they're not looking and their colleagues not showing up on their patrol.
- Eternal Darkness has an enemy example. In one chapter you are being stalked by an invisible "vampire". While you can make it visible by casting a simple spell, if you don't have time you can tell where it is when it knocks some things over (particularly in the basement when you destroy its source of power and kill it for real).
- EXTRAPOWER: Star Resistance: Maris-sama sent Nemuri to stealthily observe the Dark Force invasion of the Shakun Star and report back. Unfortunately for Maris-sama, shoot'em up mechanics don't lend well to stealth and Nemuri is eager to go on the attack, so permission to drop stealth is "officially" given as early as the Stage 1 boss.
- Final Fantasy X-2: The Gullwings dress like Leblanc goons and sneak into Chateau Leblanc to take back what was stolen from them. They get as far as having Yuna massage Leblanc disguised as a goon and even finding out the trick to get into the basement. They enter and then, over the comm... "This is Brother! How's it going?" Rikku shouts at him to shut up, that it's a covert operation. They are, of course, immediately discovered by one of Leblanc's two right-hand men, Ormi, forced into a battle, and then have to navigate a series of traps that are now activated.
- Granblue Fantasy: Anthuria runs away from a group of suitors with the help of the Captain, Lyria, and Vyrn. When the four of them decided to hide in a narrow space between two walls, the captain's hand accidentally tickles Anthuria. The Erune's sudden orgasms then gave away their presence to the suitors.
- Half-Life 2: Said word-for-word by Barney Calhoun. He announces that your group will have to sneak through the Overwatch Nexus, a pre-war public service building to take down the Suppression Device (a Combine Dark Energy Mortar) — then, as soon as he opens a door, a camera spots you.
- Halo 2: In the "Uprising" mission, after you have just taken out a few Brutes and met with some more Elites, several drop pods crash into the ground, giving the Arbiter reinforcements. One of your more Genre Savvy comrades remarks "So much for a stealthy advance".
- Hard Corps: Uprising: The stealth part in Stage 5 is optional. You can choose to go through the stealth part of the stage guns blazing.
- Heavy Rain: This can happen when Shelby's trying to sneak up on a robber. If you fail a Quick Time Event, Shelby will step on some potato chips and alert the robber.
- The Hobbit (2003): When Bilbo has to sneak past the trolls to save the dwarves, stepping on dry twigs alerts the trolls to his presence.
- Kya: Dark Lineage is not as much about as "what breaks your stealth" but more as in "do I kick their ass if they spot me, run the f*ck away or get my ass hand to me". Of course at one point you have to stealth and platform through a tight room with Wolfen guards, spikes, insta-kill floor, and what-not. What breaks your cover? You open the gate to the next level, locking down any deadly traps.
- Mass Effect:
- Mass Effect 2: In the Kasumi DLC, you can accidentally set off the alarm clock while searching Hock's bedroom for DNA. The guards come running, but only if you snuck in instead of faking security clearance.
- Mass Effect: Andromeda: Several times, Ryder and their team encounter some Remnant bots which they try to sneak past. It inevitably results in Ryder and team being spotted and having to shoot their way through anyhow. And again when trying to infiltrate the Archon's ship. They get spotted the very second they go through the door.
- Metal Gear: This can happen if you're not careful, from the singing sand in Metal Gear 2: Solid Snake to twigs on the ground in Metal Gear Solid 3: Snake Eater — notably, a lot of cases of this are deliberate traps on the part of the group you're infiltrating.
- Metroid: Zero Mission: The No-Gear Level, where an armorless Samus is forced to infiltrate the Space Pirate Mothership, operates like this. You have one chance, and only one chance, to get through stealthily, and being spotted or tripping an alarm even once permanently puts the pirates on alert and sends them actively looking for you. It is extremely difficult to pull off a successful stealth run, as it requires lightning-fast reflexes, wall jumping, and planning ahead to pull off, but thankfully just charging through while being pursued by Pirates is fairly easy (albeit not nearly as satisfying).
- Mirror's Edge: This happens so often to Faith that sneaking is more like waiting to be spotted.
- Ni No Kuni: Cross Worlds: In the Proto Mark 13 Dimensional Border, after defeating the initial group of Black Circle guards, Zera tells you to move forward, but quietly. The security door opens, you run through, only to run smack into a set of eight more. "Darn, busted!" notes Cluu.
- PAYDAY game series: while most of the missions, in theory, could be completed without breaking stealth, the players are expected to fail at some point, at which time the actual "shooter" part of the games starts. The moment is highlighted by a brief bullet time, and the players are forced to wear their masks, if they didn't already.
- Pokémon: Zorua and Zoroark can take on the appearance of other Pokémon in your party. And it can really work when battling another person... until they spot you using an attack that the Pokémon they're disguised as can't learn. The illusion also fades the moment they're hit by an enemy. Finally, because both forms of both Pokémon have one or more damage immunities, the Pokémon not taking damage can also give them away.
- Resident Evil 6 gives Ada exactly one chance to infiltrate the submarine without being seen: once the J'avo guards are alerted to your presence they sound an alert and reinforcements just keep coming. Again, like the Metroid example above, Ada has plenty of ammunition, cover, and resilience to just Leeroy Jenkins her way through but it is just so satisfying to slip through Back Stabbing guards without ever being detected.
- Star Wars: Republic Commando: Scorch will occasionally say this after an explosive charge is detonated.
- Team Fortress 2: Happens all the time playing Spy, unless you're really good, and even then you occasionally just bump into a pyro and get set aflame.
- Thief: You can be given away if you move across surfaces made of metal, stone or anything else which makes a noise when you walk on it. It isn't an instant giveaway though: one sound may make a guard suspicious, two will make him start looking around. Remain hidden and quiet and the guard will eventually conclude "Just rats." and return to patrol.
- Toe Jam And Earl: When you tiptoe past a sleeping enemy you occasionally sneeze and awaken it.
- Uncharted forces you to do this at some point — you'll always be spotted when you enter an area with the enemies unaware.
- Warframe: Due to the procedurally-generated nature of maps, an unlucky Tenno might hack open a vault door only to find a guard on the other side who happened to be looking right your way when you entered and have to taken them out before they can run to a console and trigger the alarms. Worse if it's a security drone, as those can trigger an alarm instantly upon seeing you.
- Werewolf: The Apocalypse — Earthblood: A handful of areas will automatically invoke a game over if Cahal is seen by Endron guards. Most of the time, however, being spotted just means going into Crinos and reducing everyone present to the consistency of jam.
- Winnie the Pooh's Rumbly Tumbly Adventure: Whenever Pooh enters an area with Heffalumps and Woozles, his stomach rumbles so loud that they all instantly become aware of his presence.
- World of Warcraft: To prevent stealth runs (a party consisting entirely of druids and rogues using stealth to avoid all enemies but the bosses) certain enemies are fairly arbitrarily given the ability to see through stealth. Some bosses will also alert a huge portion of the dungeon when attacked, or at least call in back-up that is likely to also drawn in other mooks that were skipped.
- Worms has an invisibility gadget that cloaks your entire team—but once a worm attacks, its position is revealed. Using Invisibility, then attacking, wastes the item.
- XCOM 2: It's not uncommon for an ADVENT patrol to walk into a position where they flank the cover of one of your concealed soldiers, which is an automatic reveal. Also, some actions will instantly break Concealment even if your soldier isn't spotted carrying them out, like planting X4 charges in an Alien Facility.
