File:Shifter.jpg|thumb|300px'''Shifter''' is an unofficial Mods|mod for ''Deus Ex'', which alters the rules of the game and adds new features.
Shifter re-integrates a few features which were left out of the game, but were later found in the game's source code. For one example, after rescuing Ford Schick from MJ-12, he's supposed to appear in Smuggler|Smuggler's hideout - and he even gives you an augmentation upgrade canister.
This makes saving him worth it, but it doesn't actually happen, so in Shifter, it does. Another example is at the airfield's helicopter bay in one of the offices. JC Denton|JC is supposed to overhear a conversation between Juan Lebedev|Lebedev and Tracer Tong in which Tong is telling Lebedev to kill JC, but Lebedev is insisting that JC can be convinced to change sides. This has been moved around since being brought back. Also, Shifter adds a handful of customized weapons, a feature that gives skill points for kills (and a stealth bonus, if applicable, at the end of each level).
Shifter also contains a modified multiplayer game featuring additional selectable player models and a new inventory system. The new system allocates 6 slots to weapons, with each weapon taking up a varying number of slots based on the weapon's size. Due to these and other changes, it is not possible to join unmodified multiplayer servers while Shifter is installed.
Author Yukichigai's mission statement is as follows: ''Shifter is my attempt at "removing the suck" from Deus Ex, what little of it there is. There are some annoying aspects of the game system, unresolved glitches, and a minor helping of unrealized potential scattered throughout this groundbreaking game. Shifter attempts to address those issues. As one person put it, paraphrased, Shifter doesn't add new content so much as improve the existing content. Shifter makes Deus Ex what it should have been, or at least one interpretation of what it should have been.''
*'''Blackjack''' - A normal baton filled with a hard substance, either lead or rebar. It does more damage than standard batons. It can be found in one of three locations, depending on JC's actions: In Paul's apartment during the player's first visit to Hell's Kitchen, on Paul Denton|Paul's dead body in the Majestic 12 base under UNATCO HQ, or inside Paul's room at the 'Ton on JC's final visit to Hell's Kitchen.
*'''Boomstick''' - A more powerful Sawed-off shotgun, with a slower pump and reload animation. Found in Jock|Jock's Apartment in Hong Kong.
*'''Internal Light Anti-Personnel Weapon''', or '''iLaw''' - A rapid-fire, Assault Shotgun-sized rocket launcher which uses Light Rockets ("L-Rockets") as opposed to normal ones. L-Rockets are the same rockets used by MJ-12 Commandos, and as such don't do the same extreme damage as normal rockets or LAMs. The iLaw is found under the Hell's Kitchen MJ12 lab that Ford Schick was held under, but on later visits, is collapsed. The iLaw is under some fallen rocks. An additional iLaw can be found in VersaLife's Pacific Rim Research Facility in Hong Kong, but only if the player returns after obtaining the Dragon's Tooth Sword's ROM Encoding specifications—specifically, when the facility is much more heavily guarded.
*'''Jackhammer''' - The mod adds in a special Assault shotgun|shotgun, the Jackhammer, behind a garage door triggered by Laser Tripwires in front of Smuggler|Smuggler's hideout. The Jackhammer has an extreme rate of fire, so fast that pulling the trigger once will shoot 5 shotgun shells instantly. Once upgraded, the Jackhammer can do incredible amounts of damage in a short time period, although it can go through all of the players shotgun ammo in under a minute, and the lengthy reload time arguably wastes more time than the Sawed-off shotgun|Sawed-off shotgun's pumping does. However, it can only be found on JC 's final return to Hell's Kitchen .
*'''Magnum''' - A special 10mm Pistol that is found on Lebedev's 747 at LaGuardia Airport. The Magnum does more damage than standard 10mm, but it's as loud as a sniper rifle and has increased recoil.
*'''Lo Bruto''' - A special Stealth pistol forged by JoJo Fine. It can only be obtained by taking it from his body. It features increased damage over the default, but it's slower, less accurate and has a smaller magazine.
*'''Precision Rifle''' - A heavily modified sniper rifle, boasting a very low shot time and a blue-tinted high-contrast scope which will highlight visible enemies. It can be found inside the foreman's shack on top of the building where JC makes his first arrival in Paris.
*'''Prototype Nanoswords, Mark I, II and III'''. All are prototypes for the mark IV, the Dragon's Tooth Sword, but they take up 3 squares in the inventory as opposed to 4 in the DTS. The Mark I does the most damage per swing when fully charged, but it also presents the most variance in damage, fluctuating between the uncharged, partially charged, and fully charged states at random; further prototypes reduce max damage but also increase the stability.
**The Mark I can be found in one of two locations, depending on whether or not Paul dies in the raid on the 'Ton: on the unconscious body of Agent Sherman, the Man in Black in charge of the MJ12 base below the UNATCO HQ, or on top of a shipping container near the back entrance to Smuggler's hideout on JC's final return to Hell's Kitchen. Paul also carries this weapon prior to JC's capture by UNATCO, except during the initial mission, and may be seen using it in combat.
**The Mark II can be found on a dead scientist in the sunken tunnels under Hong Kong
**The Mark III can be found in the PRCS Wall Cloud.
*'''Railgun''' - A modified Plasma Rifle. Rather than firing normal plasma projectiles, it fires a powerful hitscan beam that can penetrate walls. It also comes with a scope that allows the user to see targets through walls. It can be found in the house of a weapon smuggler in the Champs-Élysées in Paris. It can also be taken off of Walton Simon's unconscious or dead body at Area 51 if the player is able to defeat him.
*'''Toxin Blade''' - A combat knife dipped in poison, which causes limited paralysis on contact. It can be found under Smuggler's pillow during JC's first visit to Hell's Kitchen, This can, however, kill someone if you stab the person in the head.
*Shifter adds a touch of realism to the game by introducing random loot. Thanks to this innovation, it is possible to obtain a sword as early as on Liberty Island. Weapon mods aren't uncommon either, and one can even find a few of the coveted augmentation upgrade canisters on bodies.
*The mod alters the damage values of some weapons. For example, the crowbar's damage is set to 12 (unmodded Deus Ex had it at 6) in order to justify its 2-square inventory size. The sword has its damage doubled from 10 to 20, the stealth pistol increased from 8 to 12 and the baton from 7 to 8. Also, the one-shot PS20 has its damage tripled from 25 to 75.
*Several new types of ammo appear in the game, most notably the 10mm Explosive Ammo which greatly enhances the usefulness of handheld firearms and the Dragon's Breath Shells for the Shotguns, which upon firing expel a stream on fire that sets any target ablaze.
*Another weapon modification is introduced: the Rate of Fire mod. Typically found on NPC bodies and select locations such as the UNATCO armory. This mod increases the rate of fire of most firearms and rifle weapons by 10% of their base value.
*Many weapons now possess "alt-fire" mode. For example, most melee weapons like knives, crowbars or batons can be thrown at enemies for damage, the Sawed-Off Shotgun's chamber can be loaded with multiple shells to fire them in rapid succession and the Flamethrower can eject its whole napalm canister set ablaze, to produce a strong explosion.
*A mostly aesthetic change, cats now have their behavior altered to seem more natural, e.g. hunting rats and pigeons. This can be observed well in the Mole People Tunnels and Tonnochi Road in Hong Kong.
*NPCs are now capable of acquiring weapons that lie on the ground of their own initiative, This can cause pretty hilarious situations like in the UNATCO HQ.
*In a minor change, Paul Denton doesn't now carry a plasma rifle on his first appearance on Liberty Island. Instead, he carries nonlethal weapons which are in character for him, like the Pepper Gun.
*The Medicine Skill now allows the agent to make more efficient use of food and beverages for healing. This bonus also applies to watercoolers and water fountains (While in unmodded Deus Ex they heal 1 health point per drink, in Shifter heal from 1 for Untrained to 4 for Master).
*Shifter subjects the Augmenation system to much change:
**Augmentations can now be upgraded not only by using upgrade canisters, but also generic canisters containing the same augmentation you wish to upgrade.
**It is now possible to replace installed augmentations with new ones if all your slots are full. It is done with the help of a Medical Bot, just as if installing a new augmentation normally. It is possible to replace any augmentation in any given body region provided that you have a desirable canister (e.g. replace Power Recirculator with Regeneration). The new augmentation will also keep its Tech Level.
**The Light Augmentation now has four Techs and can be upgraded for increased luminescence.
**The Microfibral Muscle arm aug now also gives the benefits of Combat Strength as well, while Combat Strength is replaced by Electrostatic Discharge, which allows the agent to alter the AI and eventually disable bots with melee weapons.
**The Synthetic Heart augmentation can now increase the performance of most augs even beyond Tech Four, making it a choice worth considering.
**As a tribute to a long-running joke, a new Cranial aug is introduced: the Skull Gun. It can be obtained in two places: first from the vending machine during your escape from the UNATCO HQ (it got mixed up during delivery with a can of lemon-lime soda). The second canister is left behind by Gunther Hermann's corpse in Paris. The canister contains Skull Gun along with another random augmentation, so with luck it is possible to have both Power Recirculator and Synthetic Heart simultaneously.
*Shifter requires only that the player be using either the Deus Ex: Game of the Year Edition (often referred to as GOTY) or the retail version of the game with the 1.112fm patch, which can be downloaded at the Eidos site or various other game file hosts. It includes two files, DEUSEX.U and DEUSEX.INT, and these must replace the ones in the DeusEx\System folder. These must be backed up or moved to another location if you wish to remove Shifter without reinstalling the game. Replacing the files with the ones in the Shifter download will upgrade Deus Ex to Deus Ex with Shifter.
*Shifter also prevents some of the more popular exploits. You will no longer be able to sell your Pistol skill at the beginning for 1250 more skill points. You will no longer be able to use one lockpick and go into the menu. And you shouldn't be able to keep getting 100 skill points by using the switches at Vandenberg. Enabling cheats disables these bug fixes, however.
*Old, pre-Shifter save games are compatible with Shifter, but going vice versa is not compatible.
*There is a bug in Shifter that causes Walton Simons to not use the Agressive Defense System, Also, When you meet him for the first time, he has a Plasma Rifle, If you let him live and meet him again at Area 51, then he has a Railgun.