Arbitrary Headcount Limit: 25 buildable units, although you could get up to a total of 99 by buying from Starports. 2000 had much higher headcounts.
Arbitrary Minimum Range: Missile tanks could not hit a target 2 hexes or less away. If they tried, the missiles went wild and hit random locations other than the target hex.
Artificial Stupidity: The AI's move and attack patterns are very simple and predictable. This happened by mistake, as more complex strategies were programed but not well implemented due to several bugs, concrete examples include:
The AI rebuilds defenses as well as other buildings in a random fashion, and when it does the rebuilding it will crush any unit that stays upon the ruins of the building.
AI attacks on your base can be stopped by building four sections of wall at just the right spot. The AI units that arrive to attack can't manage to find a way around it, and just sit there. As long as no player units approach, they sit still, and the enemy doesn't send out more attackers.
In one mission the AI suddenly sends out a group of soldiers into an empty corner of the map for no reason at all, and they remain there, not moving, until the end of the mission.
The enemy will keep throwing units at your base defense turrets uselessly even as your offensive troops are in the process of leveling their base.
Ascended Extra: House Ordos only appears in non-canon Dune literature.
Color-Coded for Your Convenience: See The Good, the Bad, and the Evil below. In addition, regardless of chosen faction color, Atreides units and structures are always sand-colored, Ordos sickly green and Harkonnen ones dark brown. Other factions have specific palettes, notably a deep royal purple for the Sardaukar.
As modders found out while toying around with the Deviator, it doesn't change the units to your side, it turns them over to the Ordos. So if a non-ordos unit uses it, it will simply switch the target over to the ordos side, which will then simply continue attacking you.
Deflector Shields: Found on a few Ordos units. Amusingly enough, they mirror the books in that if a shielded unit is hit by a laser weapon both units will be instantly destroyed. Thankfully, this does not extend to generating an atomic explosion, however.
Determinator: Sardaukar will not be suppressed by enemy fire. Ever. Fremen however, can, which isn't exactly accurate to the books.
Expy: Several characters loosely mirror ones from the novels, most obviously Shaddam IV Corrino, who doesn't even get a name change. Elara is more complex, visually paralleling Jessica but having shades of Paul in her character.
Dune 2000 has The Engineer, who can capture buildings, allowing to build even enemy's unique units too. In the original Dune II building were captured by sending regular infantry into it. However, capturing a fully repaired building required a lot of light infantry, and only Harkonnen and emperor could produce heavies. Plus, the infantry, especially the light ones, was very slow, no match for tanks and subject for Arbitrary Headcount Limit of 25. A common tactics involved "softening" a building with quads or tanks before capturing.
The Engineer: Each side in Dune 2000 has an engineer unit much like those found in Command & Conquer. Every infantry unit was like this originally in Dune II, however.
Faction Calculus: Atreides (balanced) vs. Harkonnen (powerhouse) vs. Ordos (subversive).
Faction-Specific Endings: has three possible end victory sequences, one for each of the houses that the player can be a part of (Atreides, Harkonnen, Ordos).
Fragile Speedster: The Raider trike in Dune II and 2000, used only by Ordos, the fastest and weakest vehicle in the game. Its equivalent trikes in other factions have far less exaggerated stats.
Fog of War: Removed permanently from a zone after it is explored. You get an onscreen radar once an Outpost is built.
Out of continuity with the book and the first game. Dune 2000 and Emperor, Battle for Dune both try very hard to link themselves as prequels to the David Lynch film. It could be considered an Alternate Universe.
Dune II has little to do with Dune I, an Adventure Game by Cryo with some RTS aspects. Both games were developed simultaneously and Cryo apparently rushed it in order to beat Westwood to the punch.
Invisibility Cloak: Fremen units are perpetually invisible, unless badly injured. This is meant to represent their skill at moving and hiding in the desert.
Luck-Based Mission: Dune II becomes this whenever a Harkonnen player launches a Death Hand - for either side - since you never know where the missile is going to hit. It leads to Save Scumming on a regular basis, because if it destroys your Construction Yard, you've probably lost the game.
Manipulative Bastard: The Ordos, natch. Elara, for a more individual example. Then again, this is the Bene Gesserit's Hat.
Mobile Factory: The Mobile Construction Vehicle, though it has to deploy and become immobile to actually build anything. It can pack up and move elsewhere, however.
Mythology Gag: In Dune 2000, during some of the Ordos cut scenes, Edrico can be seen sitting in a Harkonnen Chair. This is the famous chair that was designed by H.R. Giger for the unproduced 70s Alejandro Jodorowsky's Dune film. Despite that film never happening, it is still called the Harkonnen chair and has been since produced in larger numbers and are actually for sale.
One-Hit Kill: Under certain circumstances. A Sand Worm will inflict this on anything, while Sardaukar Elites can do so to any infantry unit with their knives. This also hits both parties when a laser strikes a shield.
Palmtree Panic: The Atreides homeworld, Caladan, has hints of this in its appearance.
Path of Greatest Resistance: The enemy units were created at (and came from) the enemy base. You can follow the trail of enemies back to their base and attack it.
The Plan: The Emperor's plan in Dune 2 and Dune 2000.
Polluted Wasteland: Geidi Prime, the Harkonnen homeworld. Reflecting this, nearly every Harkonnen building has smoke stacks. Including ones that logically shouldn't, like their radar outposts, barracks and palaces.
Red Shirt Army: In Dune 2, infantry was only useful to sneak into a base to capture buildings. Using them for actual combat was guaranteed to result in a lot of screaming and a pile of corpses slowly sinking into the sand even against simple trikes. This was improved upon in later games though.
Sand Worm: Of course. Keep your units off the sand whenever possible to avoid attracting them, as they cannot be killed and will destroy your units instantly. Watch for Wormsign to know of their approach. Fremen units can move without attracting them. In Dune 2, they can be driven off by reducing them to half-health, but it takes an obscene amount of firepower.
Screw the Rules, I Have Money!: House Ordos has the weakest army which is purely comprised of hired mercenaries. But as a mercantile House that is only concerned with generating revenue to sustain the elite-class of their society, they absolutely do not care how many expendable pawns they have to buy off and send against their enemies. Just so long as they can safely get to the spice melange and harvest it for their own benefit.
Sigil Spam: Many structures incorporate their House's logo into their very architecture if not simply having it stuck on the side.
Single-Biome Planet: Arrakis/Dune is a Desert Planet as in the original novels. Also, the home planet of the Ordos is said to be "frigid and ice-covered" in Dune II and just "icy" in Dune 2000...i.e. an Ice Planet.
Space Marine: The Sardaukar are depicted as this, clad in much heavier armor then other House infantry. They wear distinctive box-shaped helmets with green view-ports, echoing their portrayal in the 1984 film.
Spawn Broodling: The Tleilaxu units, Contaminators and Leeches, attack infantry and vehicles respectively and convert them into more of themselves.
There Is No Kill Like Overkill: Dune 2 had only a limited supply of spice on a given map and when you harvested it all you better had an army capable of winning fielded or you could restart. Dune 2000's development team must have taken notice since in this game the spice keeps regenerating faster then it can ever be harvested, allowing you to saturate the entire map with tanks if you feel like it.
Worker Unit: The ubiquitous, beetle-like Spice Harvester (presented exactly as they appeared in the 1984 film) and the Construction Yard. Carryalls also function as such, automatically ferrying harvesters to and from spice fields. These carryalls are entirely automated and uncontrollable (though they will automatically ferry a damaged unit to an available repair pad).
Worm Sign: Burrowing sandworms are visible as distortions on the desert surface, but are invisible on the minimap until the little dot representing your harvester disappears.
In Dune 2000, the sandworms are followed by bolts of lightning, caused by static discharge from the sand.
You Have Failed Me: Lose too many battles and the Harkonnens will install a heart plug and pull it out, Ordos will decapitate you and hook your head up to a life support system ("Why won't they just let us die?"), while the Atreides will simply let you go, however your Fremen allies will then lay claim to your water.
The Harkonnen and Ordos openings in Emperor show your predecessor's "punishment for failure", who may be the player character from "II".
You Require More Vespene Gas: In gameplay terms the Spice is converted directly into funds, or "Solaris", as it it is offloaded into your refineries. In the novels its a kind of Unobtainium, withuncountablepurposesand powers.Dune 2000 explicitly justifies this, mentioning at various points that the houses are selling the harvested spice on the interstellar market, so funds used to power your war machine are expressly that generated by Spice sales. The stuff is that valuable.