- "Evade enemy patrols and Ghillie Snipers near Chernobyl."
- — Spec Ops description
Hidden is the eleventh Special Ops level in Call of Duty: Modern Warfare 2 and it is in the first in the Charlie tier of operations. The objective is to reach the extraction point, silently eliminating any enemies you find or avoiding them altogether along the way.
The Infinity Ward best time for Hidden is 1 minute 45.6 seconds.
Hidden takes place in Chernobyl (after the disaster), and the player must navigate their way to the extraction point, which is where the level "All Ghillied Up" began, from the shipping container area, passing through heavily infested radiated areas. The player begins the level with a suppressed Intervention and a silenced USP .45 with Tactical Knife. There are silenced weapons at the start that are able to be picked up as well: a MP5K, Mini Uzi, Striker and M1014. Swap out the pistol for one of these weapons - there is enough ammo in the Intervention to deal with the enemies on this level.
As Ghost states at the start of the level, players must watch out for radiated areas. Absorbing too much radiation will kill the player, though players aren't forced to go through an area with radiation to proceed further into the level.
There are small pockets of Ultranationalist soldiers and Ghillie snipers throughout the level. Soldiers are unaware of the player unless they have been alerted to by gunfire or nearby allies killed. Snipers are always aware of the player and are found in groups of three, equipped with WA2000s. Higher difficulties will result in small changes to enemy patrols and an additional sniper at the top of the tower at the church - however, this sniper acts much like a common guard rather than the standard sniper.
Players are also given "rating" based on how they kill their enemies, as shown below:
|Type of enemy/ type of kill||Perfect||Good||Average|
|Soldier(s)||The player must kill a soldier without being noticed||The player has killed a suspicious soldier||The player has killed an aware soldier|
|Ghillie sniper||The player must kill a sniper without being hit||The player was hit once by the sniper||The player was hit more than once by the sniper|
|Found in level|
These weapons can be found with and without attachments.
- On Hardened and Veteran difficulties there is a sharpshooter in the church's tower. However, his behavior is the same as that of a regular guard, not a ghillie sniper.
- PC players can use console commands to NoClip outside of the playable area, and since the whole map was ported from COD4 to MW2, the player can follow the entire route that is taken on the mission All Ghillied Up, all the way to the end and further into the Chernobyl factories.
- When outside of the map, following the All Ghillied Up mission route, if the player goes up the fire escape to the top floor, the player can enter a window and inside is a poster of Tanya Pavelovna, a character from Call of Duty: Finest Hour. 
- If the player continues further along the All Ghillied Up mission route, they will eventually pass by where the wild dog would be feasting on a dead ultranationalist, and enter the Complex. What is notable about this area is that in COD4, all of the upstairs rooms have their doors closed and cannot be accessed, but in this Spec Ops mission, the doors are open revealing fully modeled rooms that have televisions that can be destroyed, along with water bottles on top of tables.
- The player's character model will become blurry when they go prone.
- All TVs in the map can be interacted with by using the use button, they will turn on and show a blank RGB Color test screen.
- There are four TVs across the map; three in the main building in Chernobyl and one in a shipping container in the junkyard with the BMPs and Hind helicopters.