Dual wielding

Dual wielding is gameplay feature in which a gunman wields two sidearm weapons at once, one in each hand. This feature was first introduced into the Halo video game series in Halo 2 and later in Halo 3. It was removed from Halo 3: ODST, Halo: Reach, and Halo 4 due to gameplay considerations.

Overview
Dual wielding allows a player to use two weapons at any time. This allows players to experiment with weapon combinations to achieve the most effective outcome in combat. The feature is restricted only to small firearms such as pistols and the SMG (See list of dual-wieldable weapons). The Needler was previously made available as a dual wieldable weapon in Halo 2 but no longer in Halo 3 to balance the unexpected ease of killing a target with two Needlers.

The feature is also made available to the Elites AI units in both Halo 2 and Halo: Reach. They are typically seen dual wielding a pair of Plasma Rifles on normal or higher difficulty.

Advantages

 * 1) Enhanced firepower: When a player is dual-wielding, the two weapons in conjunction are more powerful than a single weapon of the same type. This allows for enhanced firepower, with double the ammo capacity and firing rate.
 * 2) Greater versatility: Two weapons wielded in conjunction can perform multiple roles at the same time. For example, a player could wield an M6G Magnum in one hand, allowing him/her to shoot accurately over longer range, and a Mauler in the other for close range firepower.
 * 3) More effective combos: Likewise, dual-wielding a plasma weapon and a ballistic weapon can confer a unique advantage: Plasma weapons are stronger against shields, and ballistic weapons are stronger against armor as well as other unshielded targets. For example, a player may choose to dual-wield a Plasma Rifle and an SMG at the same time. The Plasma Rifle can take down the shields of an opponent and the SMG can shred through the opponent's armor, allowing for a very fast and efficient kill. At longer ranges, a charged Plasma Pistol shot followed by a quick Magnum headshot will also kill an opponent.
 * 4) Doubled ammo reserve: When you dual-wield certain weapons of the same type, such as two SMGs or two Needlers, the player character can carry double the amount of reserve ammunition for the weapons. This is a trick also exploited when Triple wielding.
 * 5) Constant firepower: While dual-wielding, it is possible to reload or cool-off one weapon and fire the second one at the same time. This allows for a constant barrage; it generally takes longer to empty a magazine than to reload one. The only disadvantage is when reloading your automatic or long-range weapon, you may be stuck with your alternate weapon in a life threatening situation. Constant fire is helpful when you are in a place with enemies out in the open, or in point blank range where a rapid firing will result in a deadly strike.

Disadvantages

 * 1) Inability to Melee Attack, Throw Grenades, or Use Equipment: When a player is dual-wielding, the player must drop the left weapon in order to free a hand to throw grenades, and deploy equipment. This action of dropping a weapon takes time and is disadvantageous. However, if you Melee while dual-wielding, the left weapon will automatically drop by itself and the Melee will come out straight away.
 * 2) Reload/Overheat Window: When a player must reload their weapons, or if the weapons overheat, the player is vulnerable because they can't melee attack or throw grenades without dropping their weapon. Reloading a weapon also takes longer time when dual-wielding than while single-wielding the same weapon; however, for Covenant weapons, the "cool down" time remains the same, as does the Needler's reload time.
 * 3) Accuracy Decrease: Most weapons are slightly more accurate when single-wielded than when dual-wielded, such as the Plasma Rifle and the SMG.
 * 4) Consumes Twice the Amount of Ammo: If the player is carrying two of the same weapon, then they can carry twice the amount of ammunition. However, the weapons also reload from the same pool, thus using up twice the amount of ammunition per reload.

Changes between games
There have been several minor changes made to the feature in Halo 3 from Halo 2. The primary difference between Halo 2 and Halo 3 's dual wield is that the player can now fully control the reloading process. In Halo 2, the player is forced and strained to reload the two weapons simultaneously. In Halo 3, players could reload the left weapon first while keeping the right weapon ready, vice versa, or both at once, independent of each other. Another difference between Halo 2 and Halo 3 dual-wield is the alteration in the amount of damage dealt per weapon. In Halo 2, there is no change in the amount of shots needed to kill if you are single or dual wielding. In Halo 3, every weapon (with the exception of the Plasma Pistol) becomes imperceptibly weaker by varying degrees when it is dual-wielded. This becomes especially noticeable when Overshields are in use.

Dual wielding, as a player-accessible feature, was removed in Halo 3: ODST, Halo: Reach and Halo 4. With regards to Halo: Reach, the removal was due to the new weapon sandbox which could not support the overall gameplay design. Similarly, Halo 4 does not support dual wielding.

List of dual wieldable weapons

 * Halo 2
 * SMG
 * M6C Magnum
 * Plasma Pistol
 * Plasma Rifle
 * Brute Plasma Rifle
 * Needler (no longer dual-wieldable in Halo 3.)


 * Halo 3
 * SMG
 * M6G Magnum
 * Plasma Pistol
 * Plasma Rifle
 * Spiker
 * Mauler


 * Halo 4
 * Flag/M6H Magnum (Magnum given automatically when wielding the flag)

In the Halo universe
The act of dual wielding is an ineffective practice with gameplay put aside. A regular shooter would not achieve the same accuracy as he would normally would if he dual wields two weapons. There have been several occasions where regular individuals have successfully pull off this feat; Miranda Keyes dual wields a pair of SMGs, and a combination of pistol and a shotgun to fend off Covenant forces in Halo 2 and Halo 3 respectively, Gretchen Ketola dual wields a pair of SMGs in an engagement with Kojo "Romeo" Agu and Taylor "Dutch" Miles.

On the other hand, augmented humans such as the SPARTAN-IIs and SPARTAN-IIIs and species with superior physiology such as the Elites and Brutes are able to put this practice to a considerable success. SPARTAN-IIs and SPARTAN-IIIs saw no reduced performance when they dual wield a range of weapons. For example, in an ONI-led operation, Kelly-087 was still able to keep up with Fred-104 and John-117 whilst firing both of her Plasma Rifles. In another example, Douglas-042 and Alice-130 were able to perform acrobatic feats over and around the Elites while dual wielding their SMGs as they tried to unload the Spirit of Fire 's slipspace engine. Even Noble Six was still able to fend off several Elites while dual wielding a pistol and an assault rifle before he was taken down. Aside from dual wielding Plasma Rifles and Plasma Pistols, the Elites are also seen dual wielding Energy Swords.

Trivia

 * Miranda Keyes is seen dual-wielding a shotgun and a magnum in the third to last cinematic on The Covenant in Halo 3. This is not possible during any of the games and would be rather cumbersome, as after the first shot the shotgun would need to be pumped, which would need the other hand. However, she never actually fired it, and given the current situation may have simply been meaning it for intimidation. Miranda is also seen dual-wielding and firing SMGs in Halo 2, and doesn't seem to be affected by the recoil.
 * Even though the ability to dual-wield is removed for the player in Halo: Reach, enemy Elites, especially BOBs, will occasionally spawn dual-wielding Plasma rifles. Like Brute Chieftains, they cannot be assassinated once they are aware of your presence.
 * Noble Six dual-wielded an Assault Rifle and a Pistol during his/her final stand, which is impossible in any of the other games.
 * Sarah Palmer is seen dual wielding M6Hs in the trailer for Spartan Ops episodes 6 through 10.

List of appearances

 * Halo 2
 * Halo Uprising
 * Halo 3
 * Halo Wars
 * Halo: Helljumper
 * Halo Legends
 * Halo: Reach
 * Halo: Fall of Reach
 * Invasion
 * Halo 4