In the Nod campaign, Umagon's first appearance has her Neck Snap a Nod Mook. She later kills 2 more when she escapes from Nod custody. Ironically, she doesn't kill anyone in the GDI campaign cutscenes.
In the GDI campaign finale, despite being weakened by a Tiberium serum, she manages to throw off Kane's chock-hold on her, allowing Mack the chance to attack Kane.
Kane returns just as badass. As a traitor is about to be executed under continuous shouts of "Kane lives in death." Kane then appears, shouting "Kane LIVES!" Even if you know it's coming, it'll give you chills every single time.
"Rule of thumb, Hassan: You can't kill the Messiah."
The beginning of GDI's first mission shows GDI soldiers running in terror from Nod cyborgs screaming for reinforcements. Reinforcements who proceed to rain from the sky in drop pods, blasting the cyborgs to pieces and landing on their corpses.
And the last GDI cut scene has the player character, Michael McNeil, going hand-to-hand with Kane himself in Nod's Pyramid Temple. They struggle, go off-camera, shots are fired, and Kane walks back into frame, still spouting his "I'm a close second to God" gibberish, leaving the player to think McNeil is dead. Then Kane chokes, checks himself, and realizes he's bleeding, turning just in time to see McNeil running up to stab him with a giant shard of Tiberium and send him to hell with a pithy one-liner.
Kane: "I am the future! The Tiberian Sun has risen-!" (holds hands to chest, sees blood on fingers. Turns to see-)
McNeil: "NOT ON MY WORLD!" (Stabs Kane. You see the Tiberium spike jutting out of Kane's back. McNeil twists the spike and Kane falls to the floor, quite dead.) "And that's an order."
The opening Nod cutscene has a nice bit:
CABAL:A division of Hasan's Elite Guard is closing on our position. The probablility of a favorable outcome can be increased if we can return to your main base and engage the enemy as we move.
Slavik: Define 'favorable outcome', CABAL.
CABAL:They all die.
Slavik: (entirely matter-of-fact) That'll do.
The GDI opening cut scene with McNeil (Michael Bihen) being commanded by Solomon (James Earl Jones,) aka Kyle Reese and Darth Vader. After Kane's appearance Solomon offers the best GDI jump jet soldiers to retake a base, already being dispatched from the Philadelphia space station as the Kodiak cuts a path across the atmosphere.
McNeil: Let's kick some ass.
The Enemy Mine between GDI and Nod to take down CABAL.
CABAL gets a good one. In the Nod campaign, when you're trying to take CABAL's core offline It turns out the core is just a hologram, and CABAL starts launching waves of cluster missiles all over the map. The kicker: CABAL then taunts you with this line, "By the way, missile launch detected."