Separate but Identical

In real-time strategy games, usually those in which the different sides represent wildly different cultures or even different species, there will often be colour-coded sub-factions that are said to be different in terms of composition, outlook or somesuch, but in actual practice there is no difference except the visual one.

Sometimes a form of Gameplay and Story Segregation.

See Cosmetically Different Sides. Not to be confused with Separate But Equal.

Video Games

 * In War Craft 2, the manual contained quite a bit of background information on the setting, including blurbs about the different human nations and orcish clans and their differences. For example, the nation of Stromgarde is said to have an especially strong martial culture, but when they appear in the single-player campaign the only difference from the standard Alliance is that their faction colour is red rather than blue. Similarily, Alterac is orange Alliance and Dalaran is purple Alliance, and so on.
 * However, some of their AIs and starting structures had differences. Dalaran, the magocracy, had especially many mage towers and the orcish Dragonmaw Clan attacked solely with dragons.
 * More to the point, though, in Warcraft 2, the orcs and humans were indistinguishable in almost every way. The build trees for both sides were identical, up to the last stat of every single troop. Two-Headed Ogres happened to run exactly as fast as a Knight's horse, and a Dragon's fire breath worked just the same way as a Gryphon rider's magic hammer. The only difference is that the spellcasters (Ogre Mage/Paladin, Death Knight/Mage) had different spells, and their advanced archer units have different upgrades.
 * Which makes it funnier when you address how both sides would have fared on their own. The ogres and the trolls were species indigenous to the region of Azeroth meaning that if they had not joined the orcs, they would have been stuck with Grunts as their only real attack unit. On the other side, since humans made up the bulk of the ground attack forces, the orcs would have been vastly weakened. To make it more hilarious, the orcs were afraid of the freaky guys riding the horses so them finding the ogres was rather justified.
 * It was even worse in War Craft I. In that game even the spells, which again had different names, were functionally identical (for example "Summon Spiders" and "Summon Scorpions" had essentially identical effects), with three exceptions. First, the Cleric's Healing spell and the Necrolyte's (the Orc's equivalent of the Cleric) Raise Dead spell had different effects (and quite significant ones: these were the most important spells in the game). The Cleric could make a unit invisible (worthless when playing against the computer because The Computer Is a Cheating Bastard) while the Necrolyte could make a unit invincible at the cost of half the unit's health. Also, the Human Conjurer's Summon Water Elemental was noticeably weaker than the Orc Warlock's Summon Daemon, but it had a (short) ranged attack while the Daemon only had a melee attack.
 * Fortunately averted in the campaigns of Warcraft III. The Blackrock clan which appears in two missions has a Warcraft 2 tech tree, and when the blood elves break off from the Human Alliance, the human footman is replaced by an elven footman (identical stats), and the basic ranged unit is an elven archer (functionally equivalent to the standard rifleman); the rest of dwarven and human unit positions are filled by  units that are quite different from the units they replaced. Also,   has aquatic-themed units in the expansion.
 * Also present in Starcraft in the expansion when an expeditionary force from Earth shows up and has units identical to those of the original Terran faction, who are descended from exiled criminals and had been cut off from all contact with Earth for several centuries. The new faction is the in-story justification for several new Terran units, and the manual states that the UED has been spying on the local factions for generations.
 * That being said Starcraft does at least feature three races that are quite distinct.
 * Blizzard in the early planning stages wanted to have a separate UED faction but they didn't want an even number of campaigns, so they made the UED use Terran units and still have only three campaigns.
 * In the Red Alert series, during multiplayer games one can choose to play as different countries within the alliances that constitute the two sides. Though the units are basically the same, there are some small differences in terms of unit cost, construction time, armour values and so on. In Red Alert 2 each sub-faction also has a unique special unit only they can build.
 * In Company of Heroes the last mission has the Americans working with a team of Canadians to defeat the Germans, yet the Canadian forces are identical to the Americans except for the fact that their units are designated as green. This is made even more obvious when the expansion pack has Canadian forces that are exactly the same as the British soldiers except that when you click on them they say something in a stereotypical Canadian accent (rather than an English or Scottish one). This only really applies to the Canadians, though.
 * There's a bit of justification for this, since the Canadians mostly used British and American-designed weapons. Being a relatively small country they didn't have much of a domestic weapons industry, so their equipment might very well be interchangeable with the stuff being used by their allies, even though things like doctrine wouldn't be.
 * The background story of Total Annihilation is that the ARM and CORE are flesh and blood humans versus people that have transferred their minds into computers, and that this ideological conflict is the casus belli of the entire game. You wouldn't know it from the units employed in the actual game, since both sides are composed entirely of identical-looking hordes of utterly disposable machines.
 * Ditto for Supreme Commander; while the units look distinct from one another depending on their faction, and there are some mild differences in firepower and mobility (Aeon have the best early-game navy, UEF the best tanks, etc.), along with a few unique units for each one, they're more or less functionally identical and all play similarly.
 * Somewhat averted in the Supreme Commander expansion Forged Alliance where a 4th faction is introduced and all the other factions are given extra units. These tend to accentuate the differences in the factions more, although basic strategies still remain the same (go over there and stomp on that player).
 * The manual for Total Annihilation gave some blurb about how the CORE (the computer side) copied the data of their best soldiers into all their units and the ARM (the human side) responded by developing a very regimented cloning and training-from-birth program to create ideal soldiers to pilot all their units. In other words, by fighting the war for so long they almost completely converged in their methodology, despite their differing ideologies. I'm sure there's an Aesop buried in there.
 * While true for the most part, the few race differences there are are some of the best units. Core's light armor doesn't have a chance against Arm light armor, and Arm heavy tanks can't hope to win against a similar number of Core superheavy ones - which the Arm side lacks. Also, there are a few standalone units like the Arm Fido, a fast guerilla bot, and the Spider, a unit that has no offensive power but is great for stealing enemy units. Oh, and the Krogoth.
 * In the Warhammer 40000 universe, each of the major Space Marine chapters is supposed to have its own unique specialized field, with equipment and tactics to match (and some even having different organizational structures). However, in the Dawn of War computer games, the only differences are the Chapter colors and banner. This is only apparent on single-map battles or in multiplayer, however, as during the single-player campaigns only one Chapter (the Blood Ravens) is actually present.
 * That is not only so for the Space Marines. Every single one of factions whose colour schemes can be used usually have some special way of fightning, which may also lead to such illogical situations as the World Eaters Chaos Legion, servants of the martial god Khorne, using wizards and demons of Tzeentch.
 * Don't forget an Emperor's Children force sacrificing someone to summon a Bloodthirster of Khorne. That can happen too. Fun times.
 * World in Conflict has three distinctive factions (the US, NATO, and USSR) which all use their respective vehicles. In game, they are all pretty much identical, with the exception of several offensive special abilities, one tactical aid and the heavy artillery unit.
 * Age of Empires has consistently moved away from this trope.
 * The first game had everyone draw from the same tech tree, but each civilization had units it couldn't use, and bonuses to some of those it did.
 * The second game added unique units for each civilization (Japanese Samurai, British Longbowmen), and the differences got larger - especially for the Maya and Aztec civilizations, who (obviously) lacked any form of cavalry or gunpowder units.
 * The European civilizations in the third game zigzagged - some units, like Musketeers, Hussars, and most of the siege units, were shared among most factions. Others, like Strelets, Organ Guns, and almost all the units in the Ottoman arsenal, were unique to one faction. A few, such as Dragoons, Horse Archers, or Pikemen were limited to a few factions.
 * The Native Americans in the Warchiefs expansion made a major break with this trope, with unique tech trees. They did share a few gameplay elements, such as the Fire Pit.
 * The Asians were even more of a break, with virtually no shared units or technologies.
 * Age of Mythology played with this one - all factions had unique military tech trees and myth units, but shared many economic buildings and almost all non-mythological technologies.
 * Grand Theft Auto San Andreas. The Grove Street OGS hate the palatte-swapped Ballas. The only real difference between the two crews is the Ballas sell cocaine; otherwise both are filled to the brim with violent psychotics.
 * Similar goes for the two Latino gangs in San Andreas.
 * Homeworld's Kushan and Taiidan forces are pretty much palette-swapped units with different designs, but plays exactly the same way save for one unique unit each. Fighters defeat bombers, bombers attack cap ships, etc Justified in-story, as most of the advances along the tech tree are either back-engineered from captured enemy vessels or something new being thrown at you and your R&D guys coming up with a version of your own.
 * Homeworld 2 however, pulls an aversion. While some ship roles between Hiigaran and Vaygr units are analogous (i.e. Destroyers are still front-line capital ships), design differences and unit behavior means that everything, including fighting strategy is completely different. For example, while Hiigaran fighters and corvettes are invariably weak against frigates, one Vaygr corvette type is designed specifically as a frigate killer, and amassed enough (very easy due to Vaygr's Death of a Thousand Cuts doctrine), they will sink destroyers in short order.
 * Cataclysm also averted the trope rather thoroughly; instead of bombers for attacking capital ships, your fighters were modified to carry a couple of torpedoes under the fuselage. Corvettes (renamed gunships in Homeworld 2) were... Well, that's kind of complicated. Capital ships were restricted to the support role until well into the mid-game, when you finally gained access to the Multi-Beam Frigate and the Destroyer.