Part 1Update 01:
So hey, let's talk/sperg about GDI and Nod technology and aesthetics. We're only one mission into Renegade, but maybe you have gotten an inkling that each side is kind of different.
This is GDI's symbol. It's an eagle. Or a hawk. No, it's probably an eagle. The eagle is all about power, being badass, and ARE FREEDOMS, so it's a good symbol for GDI.
Here are a couple of GDI soldiers. That's a rifleman on the left and a GDI Rocket Officer on the right. Note that their uniforms have plenty of yellow in them because GDI's color is gold. A bit on the futuristic side, but they're wearing armor and uniforms that modern troops could wear.
Here are some GDI vehicles. Clockwise from the upper-left, they are the Orca Assault Craft, Medium Tank, Chinook Transport Helicopter, and Humm-Vee. The tank, Chinook, and Humm-Vee all look like modern vehicles, and the Chinook and Humm-Vee are explicitly named after their real-world counterparts. The Orca stands out as being one of the few futuristic elements in Tiberium Dawn: It look like a helicopter with jets instead of a rotor. Appropriately, it's a unit that appears close to end-game because it's new tech.
Oh yeah: The Orca is not a helicopter because it doesn't have any rotors
Here's the orbital Ion Cannon, the other sci-fi weapon that GDI uses in Tiberium Dawn. It's also a late-game element. Mission one shows it off, but it's not as devastating as most cutscenes want us to believe. I mean, yes, it is powerful, but its beam usually isn't large enough to engulf an entire base with white-hot death.
This is Nod's symbol. The scorpion tail symbolizes Nod's preference for victory through dickery. Nod uses all sorts of nasty tricks to fight, like fire, chemical weapons, nukes, assassinations, mass murder, terror bombings, etc.
Here are some of the Nod soldiers we fought in mission one. The left one is Nod Infantry, the middle one is Flamethrower Infantry, the one on the right is a Rocket Soldier. Their uniforms are red and black. Nod's colors are red and black. These are just the basic grunts, but their outfits are futuristic and quite sinister. They also give no shits about camouflage, which might be one reason Nod loses at the end of every Tiberium game.
Here are two Nod vehicles we encountered in mission one. The buggy is Nod's version of the Humm-Vee. The light tank is a faster and weaker counterpart to GDI's medium tank. They're quite stylish and menacing. I didn't notice the angry face on the front of the buggy until I took these pictures.
Renegade takes place in this world. It's a world where our troops fight against the weird and very fashionable bad guys. But here's the thing...
When Tiberium Dawn came out in 1995, the units didn't look like that. Or Nod's didn't, at least. GDI and Nod units both looked as conventional as Westwood could manage in a game with laser towers and orbital ion cannons. Soldiers looked the same on both sides and Nod's units were grayish-blue. Nod vehicles looked like they had been purchased on the cheap from third-world nations and civilian vehicle manufacturers and jury-rigged into deadlier weapons, and only endgame things like the Obelisk of Light truly have that Nod look to them. What happened? How did Nod troops go from normal-looking dudes to Darth Kane's Scarlet Stormtroopers?
My guess is that Renegade's designers cribbed from Command & Conquer: Tiberian Sun (1999). Tiberian Sun is the sequel to Tiberium Dawn and takes place in 2030. The world is going to hell because of Tiberium, but GDI and Nod get fancy sci-fi future tech to make themselves feel better about it. Nod forces show their own distinct style, which made it into Renegade. The borrowing doesn't stop at visuals, either: Tiberian Sun delved more into what Kane wants to do with Tiberium and Renegade incorporates a fair bit of that into its own plot.