Iron Curtain (Red Alert 2)

The second-generation Iron Curtain device is a Soviet superweapon in Command & Conquer: Red Alert 2 and Yuri's Revenge which renders vehicles and structures in a small area temporarily invulnerable, but kills any infantry caught in the area of effect.
==Background==
This version of the Iron Curtain device is an advancement of its predecessor, as it can target up to 9 units for a longer time (50 seconds) and with a shorter cooldown, and can also affect structures. Its output is so powerful red-tinted energy it covers its targets with is thickened to the point that it turns black, though red flashes could still be seen whenever the field was struck by weapons fire. This colouration vanishes when the Curtain's effect wears off.
Not all of the original Curtain's flaws were ironed out, however. This generation is still unable to sheath air units, making Kirov airships and airborne siege choppers ineligible for targeting, although the latter can be sheathed if deployed. Also, the greater energy output of made the curtains power lethal to infantry and dogs, unless they are garrisoned inside buildings or transports (if deployed, however, infantry can not re-enter the structure or transport until the effect wears off). This can be used offensively.
The new Iron Curtain physically resembled the original in many ways, with a large metal sphere at its apex, a wide metal base, and arcs of energy crackling from the base to the sphere.
==Game building==
===Abilities===
===Effects===
Iron Curtain protects vehicles and structures within the targeted area from all external damages. If a unit is being infected with Terror Drone, the infection is immediately eliminated. Mastermind will not take overload damage while being invulnerable. Iron Curtain also provides protection against unorthodox attacks, such as being lifted by Magnetron, mind-controlled by Yuri forces, made berserk by Chaos Drone, or chronoshifted by Chronosphere. On the other hand, the effect instantly kills all exposed infantry and organic units (like Dolphins and Giant squid).
Occupiable buildings and transport vehicles cannot be entered, but the units inside can still be evacuated as normal.
===Limitations===
Vehicles flipped by shockwaves are still destroyed. So are Harrier and Black Eagle when their airfields are removed. If an Iron-Curtained Terror Drone infects a vehicle, it is still eliminated when the vehicle is repaired. Robot tanks hovering over water still sink and become lost when their Robot control center goes offline. Non-amphibious units are also destroyed if the bridge they are standing on is demolished, or if they are cruising through a destroyed bridge when it gets repaired. If deployable vehicles like Slave miners or MCVs are protected by Iron Curtain (or Force shield), they will automatically lose the protection when they switch between their forms. Auxiliary units spawned from vehicles (like Aircraft carriers or Destroyers) do not inherit the invulnerability from their parents.
The shield does not prevent the structure from being sold, nor does it prevent units from being killed by Grinder. It has no effect on self-destruction abilities of Demolition Truck and Terrorist IFV. Positive effects, such as vehicles being repaired by Crane IFV or by Service Depot, or defused by an Engineer, or Tesla Coils and Prism Towers receiving additional energy, are not affected. Likewise, Crazy Ivans can still plant a bomb on a protected unit, which may do damage if the shield wears off before the detonation.
Possibly due to a glitch, Chaos Drones and Terror Drones may still enter an Iron-Curtained transport.
Iron Curtain effect will be overridden by Force Shield if they are used on the same structures.
===Tactics===
Offensively, the Iron Curtain is most commonly used in tank pushes, especially when facing units and structures capable of mind control. Demolition trucks under the effect of the Iron Curtain are protected from premature detonations. The weapon also allows for more elaborate attacks, like using flak tracks with engineers or terrorists. Larger infantry battalions can be eliminated from afar with the Iron Curtain as well.
Defensively, the Iron Curtain can provide protection for structures without causing power outages, unlike the Force Shield. It can also be used in tandem with it for protecting two separate sets of structures, provided that the Iron Curtain is used first.
As is the case with many superweapons, there is no hard counter. A multiple layered wall can be deployed to merely buy some time.
===AI behavior===
The AI will always build an Iron Curtain before a Nuclear Missile Silo. The AI will cast Invulnerability on specific strike forces that will be prepared and will regroup near the enemy base when the Iron Curtain is nearly ready.
====All difficulties====
The following strike forces will prioritize targeting base defenses before other structures:
* 6x Rhino Tanks
====Easy====
The following strike forces will prioritize targeting production structures before other structures: 
* 2x Rhino Tanks
====Medium====
The following strike forces will prioritize targeting base defenses before other structures: 
* 1x Apocalypse
====Medium/Hard====
The following strike forces will prioritize targeting base defenses before other structures: 
* 3x Tesla Tanks, 2x Rhino Tanks
The following strike forces will prioritize targeting production structures before other structures: 
* 1x Demolition Truck
====Hard====
The following strike forces will prioritize targeting base defenses before other structures: 
* 4x Apocalypse
The following strike forces will prioritize targeting production structures before other structures: 
* 5x Rhino Tanks, 2x Flak Tracks
==Changelog==
* Red Alert 2 patch 1.004: aircraft can now fly over structures affected by the Iron Curtain.
==Trivia==
* The AI uses Iron Curtain upon its vehicles mostly when facing defenses, rarely to destroy key structures.
* In original Red Alert 2, computer units automatically attack the player's or another computer's invulnerable unit. However, in Yuri's Revenge, they ignore the unit until its invulnerability is exhausted.
* If SEALs, Tanya or psi commandos plant C4 while using the Iron Curtain on their intended target, they will get stuck inside permanently. They can still be killed, however.
* The Iron Curtain can remove terror drones but not giant squids while latching on their victims. For the terror drone's case, this can even save ore miners or MCVs from further damage.
==Gallery==
RA2_Iron_Curtain_Device_concept_art.jpg|Early concept art
RA2_Iron_Curtain_Device_alpha_appearance.png|Alpha appearance
Iron_Curtain_(RA2).jpg|Passive Iron Curtain in a snow theater
Iron_Curtain_(RA2;_Active).jpg|Charged Iron Curtain in a snow theater
===Animations===
Iron_curtain_animation_5.gif|Buildup
Iron_curtain_animation_2.gif|Passive and damaged
Iron_curtain_animation_3.gif|Charged and damaged
Iron_curtain_animation_4.gif|Ditto
Invulnerable_animation.gif|Invulnerability
===Cameos===
Pre-release cameos, all alpha stage for the weapon:
==See also==
* Chronosphere, Allied counterpart
* Genetic mutator, Yuri counterpart