Developers Foresight / Call of Duty

The Call of Duty series does this frequently.

Call of Duty 4: Modern Warfare

• In the Call of Duty 4 level "F.N.G.", if the player triggers the target at station one and then runs back to the platform where Gaz is standing before shooting at it, Gaz will ask you what you're doing and tell you to get back to the first station. You can also get a wide array of failure messages for many circumstances, including shooting the TVs at the training course ("You endangered your squad!") or shooting too close to Price ("You almost shot Captain Price!").
  • About half of the level's objectives were Dummied Out; Price has a possible line that references it if you start doing worse at the CQB test, saying "perhaps it was a mistake to let you skip the obstacle course".
• During "Crew Expendable," if you move too far from Price after he tells the SAS team to stick together, you'll be ambushed by a single unique enemy soldier with an equally-unique Desert Eagle that will two-shot you.
• In "Charlie Don't Surf", it's possible to see an enemy technical truck driving far in the distance as you enter the town. If you shoot slightly ahead of it and view it as long as possible, there's a special animation where the driver's door opens and a corpse rolls out. This cannot be done anywhere else in the game.
  • In addition, if you take out that technical, the one that attacks you on the road won't appear, with the implication being that it was the same vehicle.
• In "All Ghillied Up", a scripted encounter involves an enemy helicopter passing over you. Normally, you're supposed to hit the deck and let it pass. There are some Stinger missiles located in the building just before that happens. Should one use a Stinger to shoot down the chopper, Cpt. McMillan will actually comment about it, sardonically telling the player to stop showing off.
• Using cheats on "Game Over" will produce a wide variety of unique effects that can't be triggered in any other way. If the player activates the "godmode" cheat and scores a hit on the Hind chasing the truck with an RPG (which is next to impossible) or kills the maximum number of enemies on the bridge before the tanker explodes (which is very difficult), the ending changes - instead of Zakhaev executing Gaz, a random SAS soldier (usually named Pvt. Cook) inexplicably gets up from the dead and melees all three Ultranationalist soldiers (including Zakhaev), with the rest of the ending proceeding normally and the player not having anyone to shoot.
  • Zakhaev has a scripted animation for when he turns around to shoot you while you're laying on the ground at the very end, where he will take three shots then start walking away. If you use cheats to survive that, once the animation ends he has regular combat AI, and will continue shooting you, even following you around if you use the "noclip" command to move. They even accounted for how a man with only one arm is supposed to reload a gun - he'll let his Deagle drop after seven shots and pull out a new gun. It's hit-and-miss, though, as he's animated to hold the Deagle like a rifle, including letting it fall on a sling so it hovers over his belly, and once he pulls out the second gun he'll simply play the normal reloading animations, apparently shoving in new magazines with a phantom limb. Also, if you use "noclip" as Kamarov and the Loyalists arrive to rescue you, you can watch as the medic continues trying to resuscitate Price after the stretcher is lifted up into the air, and the medic pounding on his chest at the end (which can't be seen in normal play).
• In "Blackout", if you follow Gaz to the fusebox instead of waiting by the door with Price, he'll tell you to go back and wait.
• During the mission before handling the nuclear bomb launch crisis, it is possible to be killed by a hangar door opening by jumping on it before it fully opens, complete with the message "You were killed by the hangar door".
• The Updated Re-release adds Makarov and Yuri to "One Shot, One Kill" as a Continuity Nod to Yuri's flashback in Modern Warfare 3. If you shoot Makarov after shooting Zakhaev, you get an achievement called "Time Paradox" for pre-empting the next two games. Shooting Yuri, on the other hand, results in a game over for "friendly fire."
• The last field in "Hunted" seems to be impossible to cross without being spotted by the sentries and triggering a running shootout as you flee to the other side to escape the helicopter. However, you can cross without being spotted by the patrolling guards if you manage to quickly get close to the one on the right, crouch and sneak up and then knife him, and then crouch and move back before the other sentries turn. You'll still get into a firefight once you get to the end of the field and enter the greenhouses beyond, though, since that cannot be skipped.
  • At the end of "Hunted" you have to shoot down the aforementioned helicopter with a Stinger missile. The helicopter is scripted to use chaff to dodge the first missile and the second one will kill it. In a lot of games, these missiles would be scripted projectiles that passes through obstacles, but in this game it's a fully rendered projectile with collision, so if the first or second missile impacts an obstacle like the one of the nearby barns, you'll need to fire it again to trigger the chaff or the killing hit.
• In "All Ghillied Up" there is specific dialogue from MacMillan if you kill the guard patrolling outside of the church in different locations, and the lookout in the tower may or may not spot the corpse depending on where you kill the patrol.

Call of Duty: Modern Warfare 2

• If you wait long enough at the basketball court during "S.S.D.D" in Call of Duty: Modern Warfare 2, a Ranger will ask you to get off the court. If you wait even longer, he asks you to wait your turn, then expresses indignation at what you're doing.
  • After you've had your turn at the opening firing range, local soldiers step up to show what they've learned. If you use noclip to step out onto the range, the soldier who's actually shooting will immediately stop until you get back off in a nice display of basic range and gun safety, despite the fact that in the released game there is no way to step out onto the range without noclip.
• If, in "Team Player", the player decides to run across the completed bridge after it's been repaired rather than getting into the Humvee, you get shot by a sniper and the game chides you with a special message that "Maybe it's safer to stay with the convoy."
• The Updated Re-release adds Yuri crawling slowly after you to "No Russian" as a Continuity Nod to his flashback sequences in Modern Warfare 3.

Call of Duty: Black Ops

• In Black Ops, some firearms are held in such a way that you can see your character's watch. When playing as Agent Hudson, his watch actually tells the correct time given by your system clock. When playing as Mason, his watch gives a completely random time that changes periodically. This is very subtle foreshadowing of the fact that Mason's grip on reality is at least partially unhinged.
• The game also has an "oversampling" mechanic for semi-auto and burst fired guns, where attempting to pull the trigger faster than the weapon can actually fire will caused trigger inputs to get intermittently skipped.^note A major improvement from World at War's anti-modded-controller measure, where exceeding a weapon's firecap by even just a bit will cause a permanent rate of fire penalty for the offending weapon for the rest of the match. The problem? For some semi-auto weapons, it is easy to exceed the firecap on accident. The M14 and FAL, in particular, will "jam" in this fashion if fired too fast. This is meant to be a deterrent against hackers, so that the M14 and FAL don't turn into death lasers.

Call of Duty: Modern Warfare 3

• In the Modern Warfare 3 mission "Turbulence", if the player attempts to reload the AK-74u or Five-Seven as the plane stalls and floats in zero-gravity for a few moments, the magazine will float away and spin in the air instead of being thrown away normally. This cannot be done with any other weapon.

Call of Duty: Black Ops II

• In Black Ops II, the Tactical Insertion equipment displays coordinates on its LCD display. The coordinates are, in fact, almost always accurate to the map that they are set in. For example, the multiplayer map "Drone" is set in Burma. If you read the coordinates and type them into Google Earth you will end up smack dab in the middle of Burma. This must have been quite a lot of work, as every single map in the game has this feature, including DLC.
  • An exception being "Cargo", as even though the harbour is depicted as being within the Singapore city centre, the Tac Insert's coordinates actually point to the Pasir Panjang cargo terminal, which is a few kilometres west of downtown.
  • A double-instance comes with the DLC map "Cove", set on an island from which you can see the boat from the vanilla map "Hijacked". Sure enough, the coordinates on the Tactical Insertion for Cove aren't that far away from those for Hijacked.
• The KSG fires regular buckshot in singleplayer, but slug rounds in multiplayer. The models for the shells loaded into the multiplayer version are properly green, like real-world slugs.